The 32 best Friends cameos of all time

 Press still of Billy Crystal and Robin Williams in an episode of Friends.
Press still of Billy Crystal and Robin Williams in an episode of Friends.

So no one told you that life was going to be this way. But hopefully you made a lot of… friends in the process. Since its original run on NBC between 1994 and 2004, Friends has enjoyed rare status as an enduring pop culture staple and cornerstone for the modern sitcom. Even now, could it be any bigger?

Starring an ensemble cast made up of Jennifer Aniston, David Schwimmer, Courteney Cox, Lisa Kudrow, Matt LeBlanc, and Matthew Perry, Friends’ deceptively basic premise – that of six lively twenty-somethings living in an impossibly spacious New York City apartment – was actually a novel idea for its time, when most sitcoms centered on suburban family households.

With over 230 episodes across 10 seasons, plenty of Hollywood mega-stars have naturally passed by Central Perk for some laughs. From those just starting out in their careers to certified royalty wanting a little fun on TV, Friends was truly a revolving door of who’s who. To celebrate the show’s ongoing legacy, here are 32 of the best celebrity cameos and guest roles ever in the history of Friends.

32. Charlton Heston, “The One With Joey’s Dirty Day” (Season 4, Episode 14)

Charlton Heston stands in his dressing room in a cop costume
Charlton Heston stands in his dressing room in a cop costume

As an actor, Joey stinks – literally. After a long weekend fishing trip with his father, Joey is late to the set of his newest acting job with none other than The Ten Commandments’ Charlton Heston (playing himself) as his screen partner. Hoping to scrub the fishy smell off himself, Joey sneaks to Heston’s dressing room to shower, only to incur the wrath of the man who played Moses. But after tensions die down, Heston offers Joey some advice: No matter how badly he thinks he stinks, he must never use the man’s shower.

31. Jean-Claude Van Damme, “The One After the Super Bowl, Part 2” (Season 2, Episode 13)

Jean Claude Van Damme in an army uniform in an episode of Friends
Jean Claude Van Damme in an army uniform in an episode of Friends

Airing in 1996, just moments after the Dallas Cowboys stood victorious as the year’s champions of the NFL, the Friends episode “The One After the Super Bowl” aired as an hour-long extravaganza that revolutionized post-big game programming. The red-hot sitcom crammed the episode with guest stars, including Julia Roberts, Brooke Shields, musician Chris Isaak, and even action star Jean-Claude Van Damme.

When Ross’ monkey is featured in a new movie, Outbreak 2: The Virus Takes New York, the girls make close acquaintances with JCVD in one of many instances where the celebrity guest plays themselves. However, the Bloodsport star was allegedly not popular among the cast and crew. In a 2021 oral history feature for The Hollywood Reporter, director Michael Lembeck recalled that a deleted scene had Van Damme kiss both Courteney Cox and Jennifer Aniston. During filming, the women told Lembeck how uncomfortable they were with Van Damme unnecessarily using his tongue.

In a 2023 interview with the New York Post, Van Damme looked back on his performance, saying he was “ashamed of myself,” though he only said it was because of his acting.

30. Sarah, Duchess of York, “The One with Ross’ Wedding, Part One” (Season 4, Episode 23)

Sarah, Duchess of York in her guest role on Friends
Sarah, Duchess of York in her guest role on Friends

When the gang whisk off to London for Ross’ wedding, Joey of all people runs into an actual member of the Royal Family: Sarah, Duchess of York, birth name Sarah Ferguson.

After Joey is duped into buying a ridiculous hat at a souvenir shop (run by Virgin’s billionaire owner Richard Branson, another noteworthy cameo in the show’s history) he runs into “Fergie” while trying to tour Buckingham Palace. She finds the hat “dashing,” too.

In the nonfiction book I’ll Be There For You: The One About Friends by TV journalist Kelsey Miller, it is revealed that Ferguson did the cameo at the insistence of her daughters who were big fans of the show. The book added that the cameo even alleviated some of Fergie’s negative public image among the British public at the time. That’s London, baby.

29. Ralph Lauren, “The One with Ross’ Teeth” (Season 6, Episode 8)

Ralph Lauren stands with his hands in his pockets in an elevator in his cameo on Friends
Ralph Lauren stands with his hands in his pockets in an elevator in his cameo on Friends

For several seasons of the show, Rachel is employed at the offices of iconic fashion label Ralph Lauren. In an episode of Season 6, Rachel rides the elevator with her supervisor and insists that she did not make out with the man at the top. Because when you speak of the devil and he appears, none other than Ralph Lauren steps into the elevator, quietly riding to the top with thumbs in his jeans like he’s his own model.

Fun fact: For the show’s 25th anniversary in 2019, Ralph Lauren launched a limited collection directly inspired by the wardrobes of the show’s characters.

28. Jane Lynch, “The One Where Estelle Dies” (Season 10, Episode 15)

Jane Lynch as a realtor walks Chandler and Monica through a new home in Friends
Jane Lynch as a realtor walks Chandler and Monica through a new home in Friends

The first celebrity “cameo” on this list where the guest doesn’t play themselves, comedy star Jane Lynch was early in her career when she appeared in the last season of Friends in the small part of a realtor. When Chandler and Monica begin looking for a home, they visit one and quickly find who their neighbor might be: Chandler’s infamous ex-girlfriend, Janice (played by Maggie Wheeler).

In November 2020, Lynch notably appeared in an episode of Watch What Happens Live with Andy Cohen and put down online rumors that she ever auditioned for the role of Phoebe on Friends.

27. Lea Thompson, “The One with the Baby on the Bus” (Season 2, Episode 6)

Lea Thompson guest stars as a passerby on the street in Friends
Lea Thompson guest stars as a passerby on the street in Friends

Before sitcoms like Brooklyn Nine-Nine and New Girl did special one-night crossovers, there was Friends and Caroline in the City, the latter of which starred Lea Thompson (Back to the Future) and ran for four seasons on NBC. In a Season 2 episode of Friends, Thompson briefly appears as Caroline Duffy, who runs into Joey and Chandler and mistakes them for a gay couple.

Meanwhile, over on Caroline in the City’s side of the convergence, Chandler is shopping at a video rental store when he tries to use a VHS copy of The Piano (it was the ‘90s) to pick up Caroline’s neighbor and best friend, Annie Spadaro (played by Amy Pietz).

26. Jim Rash “The Last One” (Season 10, Episode 18)

Jim Rash plays a paranoid passenger next to Rachel in Friends
Jim Rash plays a paranoid passenger next to Rachel in Friends

Because Friends can’t resist getting a last one in, eventual Community star and Oscar-winning screenwriter Jim Rash had a small role as a nameless, nervous flight passenger seated beside Rachel in the series finale. More of a bit part than an actual cameo – Rash’s appearance was several years before he played a hapless community college dean for another cult NBC show – Rash nevertheless makes an impression by wildly misinterpreting Rachel’s phone call to Phoebe.

25. Dermot Mulroney (Season 9)

Dermont Mulroney guest stars in Friends as a coworker and love interest for Rachel in Friends
Dermont Mulroney guest stars in Friends as a coworker and love interest for Rachel in Friends

Dermot Mulroney was already a movie star (including starring opposite Julia Roberts in the smash hit My Best Friend’s Wedding) when he appeared on Friends for a memorable three-episode run in the penultimate season. Introduced as a sleazy workplace rival to Rachel, his unexpected demonstrations of warmth eventually win her over. Rachel briefly falls for him and the two share a passionate kiss on the apartment rooftop, to the utter heartbreak of Ross. By this point, the show was on the long road to getting its two main characters back together, with Mulroney being one steamy speed bump along the way.

24. Gabrielle Union “The One With the Cheap Wedding Dress” (Season 7, Episode 17)

Gabrielle Union guest stars on Friends, wearing a denim jacket and flirting with Ross
Gabrielle Union guest stars on Friends, wearing a denim jacket and flirting with Ross

Friends has rightfully received flak for being overrun with white characters despite its setting in one of the most diverse cities on Earth. This only makes the guest appearance of Gabrielle Union all the more noteworthy. As “Kristen,” Union plays a lifelong New Yorker who catches both Ross and Chandler’s attention simultaneously, igniting a short war of romance between them.

In a 2017 interview with the Free Library of Philadelphia, Union recalled she was mistreated on the set of Friends by being talked down to by the show’s producers who underestimated her experience. (Prior to her Friends episode, Union starred in the hit film Bring It On with other credits in 10 Things I Hate About You, She’s All That, and TV shows like 7th Heaven.) In 2020, to encourage voters to participate in the election, Union hosted a Zoom reading of the Friends episode “The One Where No One’s Ready” with an all-Black ensemble that starred Sterling K. Brown, Ryan Michelle Bathe, Uzo Aduba, Aisha Hinds, Jeremy Pope, and Kendrick Sampson.

23. Hugh Laurie, “The One With Ross’ Wedding, Part Two” (Season 4, Episode 24)

Hugh Laurie scolds Rachel on a plane in Friends
Hugh Laurie scolds Rachel on a plane in Friends

Long before he was Dr. Gregory House, British actor Hugh Laurie diagnosed Rachel as a judgemental nameless co-passenger on Rachel’s flight to London. In his more natural English accent, Laurie reminds Rachel that yes, she and Ross were on a break, and warns her that her intentions to break up Ross’ wedding is a terrible thing to do.

When Laurie appeared on Friends, he was already a known figure in the UK from programs like Blackadder. But as far as Hollywood was concerned, his performance telling Rachel off is less “cameo” and more star-in-the-making; Laurie’s fame would grow tenfold with the premiere of House in 2004. But the actor’s stardom has only made his Friends appearance all the more incredible in retrospect, and he is largely responsible for carrying the importance of knowing that Ross and Rachel were, in fact, on a break.

22. David Arquette “The One with the Jam” (Season 3, Episode 3)

David Arquette sits next to Phoebe on a stoop in Friends
David Arquette sits next to Phoebe on a stoop in Friends

Just weeks before the release of Wes Craven’s horror classic Scream, starring Friends’ own Courteney Cox and David Arquette, Arquette appeared in a Season 3 episode as Malcolm, a love-drunk stalker of Phoebe’s twin sister Ursula. Believing Malcolm to have a good heart, Phoebe begins dating Malcolm as a way to help him get over her manipulative twin sister. But Phoebe breaks it off when she realizes Malcolm’s attachment to Ursula is just a bit too strong.

21. Bob Balaban, “The One with Joey’s Bag” (Season 5, Episode 13)

Bob Balaban guest stars as Phoebe's dad, wearing a coat and scarf, in Friends
Bob Balaban guest stars as Phoebe's dad, wearing a coat and scarf, in Friends

For several years, Phoebe spoke about her father Frank only in hushed whispers. Which is why you can hear the studio audience gasp when the estranged Frank Buffay walks into Phoebe’s grandmother’s funeral. Filmmaker and comedian Bob Balaban plays the part of Phoebe’s deadbeat, neurotic biological father. While the two are hostile at a later meeting at Central Perk, Phoebe realizes just how deep their connection runs when Frank’s lullaby was in the same melody as Phoebe’s own piece, “Smelly Cat.”

20. Jason Alexander “The One Where Rosita Dies” (Season 7, Episode 13)

Jason Alexander guest stars on Friends as a depressed office worker
Jason Alexander guest stars on Friends as a depressed office worker

Need some toner? In what could be the closest thing to a crossover of Friends and Seinfeld, Jason Alexander plays Earl, a depressed office supply buyer suffering from loneliness. Because Phoebe is Phoebe, she takes it upon herself to find and meet Earl and convince him not to kill himself by helping him make friends at his work. The efforts are sadly fruitless, but it’s safely assumed that Phoebe – who lost her mother to suicide – became the friend that Earl needed.

19. Kristin Davis, “The One with Ross’ Library Book” (Season 7, Episode 7)

Kristin Davis sits on Joey's chair in his apartment with Phoebe and Rachel in Friends
Kristin Davis sits on Joey's chair in his apartment with Phoebe and Rachel in Friends

After Joey has a meaningless one night stand with a woman named Erin, Joey becomes dismayed when Erin ends up vibing really well with the other girls. Because life works in funny ways, Joey begins catching feelings only for Erin to end up detached due to a lack of a “spark.” Even late into Friends’ run, the series found ways to expand its characters’ dimensions by revealing Joey as someone who has to do the chasing to feel validation.

Two years into her starring role on HBO’s Sex and the City, Kristin Davis memorably played the part of Erin. In 2019, Davis told The Today Show that she was actually “nervous” about the role despite her plentiful experience.

"Sex and the City was in production, but I was nervous to be the tiny character of Erin [on Friends], losing sleep, partly because of the live audience, but partly because you’re in this world that has been created that is so alive and so specific and you’re trying to make sure you’re fitting yourself in there properly,” Davis said. “I remember, like, 'Will I set that joke up okay? Will Matt be happy? Will I just go blank?’ Things go through your head when you’re in those situations that are heightened like that. Obviously, it was the highest of the high at that point.”

18. Gary Oldman, “The One with Monica and Chandler’s Wedding, Part One” (Season 7, Episode 23)

Gary Oldman guest stars as an actor in a war drama while holding a water bottle in Friends
Gary Oldman guest stars as an actor in a war drama while holding a water bottle in Friends

Highly decorated stage and screen star Gary Oldman got himself an Emmy nomination for the part of Richard Crosby, a prominent actor (who lost an Oscar three times) that a starstruck Joey works with on a new World War I drama. Though Joey is excited to share screen time with one of his all-time favorites, he quickly finds out his idol can be a mouthful – literally. Joey is dismayed when Crosby douses him with spit from his passionate performances.

In an episode already crammed with guests like Kathleen Turner, Elliot Gould, and Morgan Fairchild, Gary Oldman commands everyone’s attention even on the small screen.

17. Selma Blair, “The One With Christmas in Tulsa” (Season 9, Episode 10)

Selma Blair stars as the fun and tempting Wendy in a Christmas episode of Friends
Selma Blair stars as the fun and tempting Wendy in a Christmas episode of Friends

It’s Christmas time when Chandler, now married to Monica, is thousands of miles away in Tulsa, Oklahoma for work. He finds himself alone – with sexy coworker and Tulsa branch manager Wendy, played by Selma Blair, whose own marriage is on the rocks and looking to have an extra-marital Christmas treat. Things resolve when Chandler walks in through the door of the New York apartment at the last minute (having resigned from the company), but Selma Blair’s charismatic performance as the exciting and tempting Wendy is enough to wish she had more than just one episode in the series.

16. Brooke Shields, “The One After the Super Bowl, Part One” (Season 2, Episode 12)

Brooke Shields looks shocked next to Ross in Friends
Brooke Shields looks shocked next to Ross in Friends

As part of the star-studded Super Bowl episode, model and actress Brooke Shields joined the party in a guest appearance as Erika Ford, a lunatic fan of Joey who actually believes him to be Dr. Drake Ramoray (Joey’s role on Days of Our Lives). It’s only with the help of his quick-thinking friends, who make up a cliche backstory involving Drake’s evil twin, that Joey gets rid of Erika, but not before getting an impromptu shower from thrown drinks.

In 2019, Shields revealed in a BUILD Series video interview that her Friends appearance led to her landing her own TV sitcom, Suddenly Susan, about a magazine writer in San Francisco that ran for four seasons and aired over 90 episodes.

15. Winona Ryder, “The One with Rachel’s Big Kiss” (Season 7, Episode 20)

Winona Ryder tries to kiss Rachel again in Friends
Winona Ryder tries to kiss Rachel again in Friends

In a Season 3 episode of Friends, each member of the group makes a “freebies” list, made up of celebrities that they claim the right to sleep with even if they’re in a committed relationship. The funny thing about that moment is how predictive it was, with a few of the named celebrities showing up as themselves or in different roles.

Winona Ryder, a prominent movie star in the 1990s, was on Ross’ list. Years later in a 2001 episode, Ryder played Melissa, a former sorority sister of Rachel’s who shared an unforgettable drunken kiss with her back in the day. In “The One with Rachel’s Big Kiss,” Melissa resurfaces in New York, and Rachel again kisses Melissa to prove a point. But the moment overwhelms Melissa, who reveals she’s harbored deep feelings for Rachel for so many years.

Since its airing, the episode and its onscreen kiss between leading Hollywood women has received negative attention as both a cheap ratings ploy (intended to help Friends regain depleting viewership) and a stunt at the expense of the LBTQ+ community. Still, Winona Ryder is an indisputably talented actress who makes the most of her role with sharp comic timing, a dash of sympathy, and overall chemistry with her primary scene partner in Jennifer Aniston.

14. Isabella Rossellini, “The One with Frank Jr.” (Season 3, Episode 5)

Isabella Rossillini walks into Central Perk and is approached by Ross in Friends
Isabella Rossillini walks into Central Perk and is approached by Ross in Friends

As part of a freebies list, Ross also named Italian actress and model Isabella Rossellini, before bumping her off in favor of Winona Ryder and ice skater Dorothy Hamill. At the very end of that episode, Isabella Rossellini walks into Central Perk, giving Ross the chance to live out a once-in-a-lifetime opportunity. Of course he’s Ross, so he botches in spectacular fashion. Still, Ross gets points for trying. Who can actually say they’ve walked up to their celebrity crush and shot their shot? (Actually, a lot of people in Hollywood.)

13. Kathleen Turner, “The One with Chandler’s Dad” (Season 7, Episode 22)

Kathleen Turner guest stars as Chandler's drag performing father, wearing a bedazzled gown, in Friends
Kathleen Turner guest stars as Chandler's drag performing father, wearing a bedazzled gown, in Friends

As part of a freebies list, Chandler names Jessica Rabbit, the voluptuous vixen of the half-animated movie Who Framed Roger Rabbit. In a funny turn of events that could give Freud a stroke, Kathleen Turner, who voiced Jessica Rabbit, later appeared in Season 7 as Chandler’s trans father. She’s now a Las Vegas drag show performer under the name “Helena Handbasket.” What begins as an unexpected shock gag becomes poignant in its exploration about love and understanding, even if Friends handles things in a distinctly awkward ‘90s manner.

12. Helen Hunt, “The One with Two Parts” (Season 1, Episode 16)

Helen Hunt guest stars as a visitor from Mad About You in Friends
Helen Hunt guest stars as a visitor from Mad About You in Friends

OK, a little backstory: Lisa Kudrow not only played Phoebe, but also her “totally a Scorpio” evil twin sister Ursula, who originated in another NBC sitcom Mad About You starring Helen Hunt and Paul Reiser. In a Season 1 episode of Friends, a network crossover stunt was engineered that allowed Helen Hunt and Leila Kenzle (who starred in Mad About You as Fran) to briefly appear at the Central Perk and mistake Phoebe for her sister. This was the first of several crossovers in Friends’ wild history to intertwine with other shows.

11. Sean Penn, “The One with the Halloween Party” (Season 8, Episode 6)

Sean Penn wears a sweater with planets on them in the Halloween episode of Friends
Sean Penn wears a sweater with planets on them in the Halloween episode of Friends

At one point, Ursula nabs herself an impossibly sweet man, and it’s up to Phoebe – or rather, Supergirl – to stop her. In the now-iconic Season 8 episode set at Monica’s Halloween party at the apartment, Phoebe meets Eric (played by film star Sean Penn), a kind-hearted school teacher engaged to Ursula. When Phoebe finds out that Eric has fallen victim to Ursula’s usual lies, Phoebe does her best to set things right.

Behind the scenes, episode director Kevin S. Bright observed that Sean Penn had difficulties as a movie actor adjusting to the style of TV. “I think the least successful one was Sean Penn on the show,” Bright told Metro.co.uk in 2018. "Just the style of the production wasn’t what he was used to, doing a show like that, so there was a little deer in the headlight affect [sic]."

10. Soleil Moon Frye, “The One with the Girl Who Hits Joey” (Season 5, Episode 15)

Soleil Moon Frye dates Joey in Friends
Soleil Moon Frye dates Joey in Friends

What happens when Punky Brewster walks into Central Perk? Joey gets hurt. Literally. In a Season 5 episode, actress Soleil Moon Frye guest stars as Joey’s cheerful new girlfriend Katie, who doesn’t realize her own strength in her annoyingly painful arm punches. (See Joey wear six sweaters like it’s Iron Man armor to absorb the impact.) When Rachel gives Katie some tough love back, Katie asks Joey to stick up for her, only for Joey to realize he can do one thing to finally save himself from bruises: absolutely nothing.

9. Chrissie Hynde, “The One with the Baby on the Bus” (Season 2, Episode 16)

Chrissie Hynde performs with her guitar in the Central Perk on Friends
Chrissie Hynde performs with her guitar in the Central Perk on Friends

Season 2’s “The One with the Baby on the Bus” not only had Lea Thompson, it also guest starred rock legend and Pretenders frontwoman Chrissie Hynde. As “Stephanie Schiffer,” Hynde takes over as the new Central Perk in-house musician, who performs a beautiful acoustic cover of “Angel in the Morning” (which was later featured on the show’s CD soundtrack). Not only did Schiffer wow audiences with her hypnotic performance, she also co-wrote with Lisa Kudrow “Smelly Cat,” Phoebe’s one and only real song.

8. Julia Roberts, “The One After the Super Bowl, Part Two” (Season 2, Episode 13)

Julia Roberts hooks up with Chandler on the couch in Friends
Julia Roberts hooks up with Chandler on the couch in Friends

That epic Super Bowl episode also includes movie star Julia Roberts guest starring as “Susie Moss,” a movie makeup artist who grew up going to school with Chandler. When the two reconnect as adults they begin a hot whirlwind fling, before Susie reveals it was all just a ploy to get back at him for a childhood prank. At the time, Roberts was dating Matthew Perry, which can explain why their onscreen chemistry is so visibly electric.

7. Ben Stiller, “The One with the Screamer” (Season 3, Episode 22)

Ben Stiller yells at Ross in front of the Central Perk in Friends
Ben Stiller yells at Ross in front of the Central Perk in Friends

Shortly after Chandler and Rachel’s breakup in Season 3, Rachel starts dating Tommy, a man whose hot temper radiates like nuclear waste. Ben Stiller guest stars in this memorable 1997 episode, his stardom rising from movies like Flirting With Disaster and his own short-lived MTV series The Ben Stiller Show.

Though Tommy puts on a nice face for Rachel, everyone else is shocked by how much of a dangerous bully Tommy really is. It’s not until Tommy loses it on Joey and Chandler’s baby farm animals that Rachel learns Tommy’s true nature, prompting him to leave in a huff.

6. Jeff Goldblum, “The One with the Mugging” (Season 9, Episode 15)

Jeff Goldblum coaches Joey in acting school in Friends
Jeff Goldblum coaches Joey in acting school in Friends

Friends always, uh, found a way to get the biggest faces in Hollywood onto its set. In a Season 9 episode of the sitcom, Jurassic Park and Independence Day star Jeff Goldblum plays the role of a theater director who isn’t quite sure if Joey is being sincere in his admiration. Essentially playing himself, Jeff Goldblum praises Joey and his “squirmy” performance in rehearsals, only to learn too late that Joey was just holding in a bladder of pee the entire time.

5. Rebecca Romijn, “The One with the Dirty Girl” (Season 4, Episode 6)

Rebecca Romijn flirts with Ross outside the Central Perk in Friends
Rebecca Romijn flirts with Ross outside the Central Perk in Friends

In a Season 4 episode, actress and model Rebecca Romijn plays a drop-dead beautiful Ph.D candidate who starts dating Ross. But to Ross’ horror, he learns her apartment may be the filthiest living space in all of New York. (Annoyingly, Rebecca hates Ross’ apartment because of a “weird smell.”) It takes a rat caught in a bag of potato chips to crawl up Ross for Ross to finally break things off, though Monica obsesses over the challenge of cleaning the place up.

4. Susan Sarandon, “The One with Joey’s New Brain” (Season 7, Episode 15)

Susan Sarandon holds Joey's face in Friends
Susan Sarandon holds Joey's face in Friends

Another “freebie” on the list who wound up on the show, Susan Sarandon guest stars as “Jessica Lockhart” in a Season 7 episode as a co-star of Joey on Days of Our Lives. After Joey unwittingly reveals to her that she’s being written out of the show, the two end up hooking up.

In a 2021 interview with Us Weekly, Sarandon had nothing but kind words about her experience on the show. She was practically invited by the producers to appear, and after learning her character was a soap opera star, Sarandon said she wanted to be dressed with “a really big wig.”

On working with Matt LeBlanc, Sarandon praised him and said, “I’d work with him again in a flash.”

3. Reese Witherspoon (Season 6) and Christina Applegate (Seasons 9 and 10)

Reese Witherspoon wears a black sweater at the Central Perk in Friends
Reese Witherspoon wears a black sweater at the Central Perk in Friends

The Greene sisters are a wild bunch, and it’s a miracle that Rachel is anything close to normal.

In separate episodes across Seasons 6, 9, and 10, Witherspoon and Applegate (who won an Emmy for her performance) guest star as Rachel’s sisters Jill and Amy, respectively. Both are incredibly reckless, from Jill using her dad’s credit card to buy a friend a boat to Amy piercing a baby’s ears. Both women enter the apartment like a hurricane, creating frictions among the group – like Jill throwing herself at Ross, who is trying to get back with Rachel – before leaving some kind of carnage behind.

2. George Clooney and Noah Wyle, “The One with Two Parts, Part Two” (Season 1, Episode 17)

George Clooney and Noah Wyle both play alternate versions of their ER characters on Friends
George Clooney and Noah Wyle both play alternate versions of their ER characters on Friends

Importantly not a crossover in the strictest sense, ER stars George Clooney and Noah Wyle appear as characteristically similar doctors in a 1995 episode of Friends. They’re basically their ER characters, just under different names. The doctors go on a double date at the apartment with Rachel and Monica, only for things to go horribly wrong after they argue about the possible insurance fraud they’ve committed.

At the same time Friends was a smash hit as a TV sitcom, ER was just as big (if not bigger) as the era’s premier medical drama that also had a long list of memorable guest stars. “The One With Two Parts, Part Two” basically captures a bygone zeitgeist in the medium’s history.

1. Billy Crystal and Robin Williams, “The One with the Ultimate Fighting Champion” (Season 3, Episode 24)

Robin Williams and Billy Crystal appear as Central Perk patrons in Friends
Robin Williams and Billy Crystal appear as Central Perk patrons in Friends

Unscripted. Unplanned. Unreal.

While filming the 1997 comedy Father’s Day, Billy Crystal and Robin Williams wandered onto the set of Friends and were invited by the show’s writers to do a cameo. For the cold open to the Season 3 episode “The One with the Ultimate Fighting Champion” – which also guest starred comedy actor Jon Favreau, who went on to direct blockbusters like Iron Man and The Mandalorian – Williams and Crystal improvised a hilarious scene about one of their wives’ infidelity with a gynecologist while seated uncomfortably close to the show’s main stars.

At just two minutes long, Crystal and Williams tear it up as strangers who explode on each other after Crystal’s character reveals himself to be the man Williams’ wife is sleeping with. Revisit the scene and watch everyone closely. You can see them all trying their best not to laugh, because no one told them it was going to be this way.