Megan Fox wore a fierce ballgown and comfy trainers for Kravis' wedding

Celebrity wedding guest outfits are perfect to peruse when you are deciding what to wear for the next nuptials in the calendar. In addition to having access to some of the best designers, A-listers often have stylists behind the scenes helping ensure their looks are spot-on.

From the demure dress Katy Perry wore to Ellie Goulding's big day to Pippa Middleton's royal wedding-approved midi and Emily Ratajkowski's red carpet-worthy reception gown, there's no shortage of wedding guest outfit inspo here.

Scroll through to see what celebs wore for their nearest and dearest's weddings.

Megan Fox and MGK went for coordinating punk-y looks to celebrate Kourtney Kardashian and Travis Barker's epic Italian wedding.

Proving that you can wear black to a wedding, Megan opted for a moody-toned Zuhair Murad number with a beaded bodice and glossy taffeta skirt. While the 36-year-old was originally snapped wearing a pair of heels, in her latest Instagram, Megan reveals that she actually swapped them for a pair of matching Vans, presumably so she could bust a move on the DF (scroll through to see the pic). Amazing.

As for MGK, the artist went for a blue leopard print suit, black shirt and layered necklaces. Yep, these two never do things in halves.

See the original post on Instagram

To celebrate her brother, Frankie Grande's wedding to Hale Leon, Ariana Grande went for a sleek black custom co-ord set by Vera Wang. The custom black lamé sculpted bra top matched a skirt with a thigh-high slit, which could be interpreted as a subtle nod to the Star Wars theme of the wedding (remember Princess Leia's sculpted gold bikini look?). To finish it off, Ari added an oversized black bow to her signature high ponytail, coupled with dainty cat-eye eyeliner.

See the original post on Instagram

Hailey Bieber proves that the whole 'you can't wear black to a wedding' rule is total BS in this incred LBD (little black dress) by AZ Factory, which she wore to a wedding with Justin - who sported a relaxed blue suit and Panama hat.

See the original post on Instagram

Beyoncé wore a fitted ivory midi dress with matching platform heels for sister Solange's wedding in New Orleans.

Katy Perry looks radiant in this pastel watercolour-inspired midi worn under a powder blue coat with complementary accessories for Ellie Goulding's wedding.

The Game of Thrones cast was in full attendance for Rose Leslie and Kit Harington's nuptials. Sophie Turner and Maisie Williams coordinated looks with black and red colour combos.

While Emilia Clarke went for a more muted pastel A-line dress with a blush pink overcoat.

Dressed as a Bond girl dipped in liquid gold, EmRata was a vision at Marc Jacobs' wedding reception in NYC, finishing the look with simple metallic accessories and deep red eyeliner.

Priyanka Chopra sported a lavender skirt suit at Meghan Markle and Prince Harry's royal wedding.

Cara Delevinge was a bridesmaid for sister Poppy Delevingne's wedding, for which she wore this V-neck white dress with flutter sleeve details.

Princess Diana famously nailed the wedding guest fashion brief, and this mint green and cream look (complete with the matching hat) is a case in point.

No wedding date will give you the loving stare quite like a sister. Case in point: the Hadid gals, looking gleefully overjoyed as they attended Marc Jacobs and Char Defrancesco's wedding in complimenting slick trouser suits paired with pointed stiletto heels.

Forget the floral maxi, an '80s power suit is a showstopping alternative wedding guest outfit, ideal for an evening reception in the city and worn masterfully by Kaia Gerber, of course, as she attended Marc Jacobs' big day.

Naomi Campbell donned a Balmain cape and sheer polka dot bodice for Marc Jacobs' nuptials and looked incredible, debunking the 'you can't wear black to a wedding' myth.

All white and absolutely stunning, Ashley Graham attended Sophie Turner and Joe Jonas' reception dinner in France, along with husband Justin Ervin, in this thigh slit white spaghetti strap dress.

Looking beautifully preppy, Pippa Middleton sported this Victorian-inspired Kate Spade dress and plush velvet Alice band for the wedding of Lady Gabriella Windsor.

Over the years, Victoria and David Beckham have proved that no other duo does a couple dressing quite as well. They always look brilliant, but especially so here at footballer Sergio Ramos' wedding to Pilar Rubio. These bright fuchsia heels are *chef's kiss*.

Wearing traditional Indian dress, Sophie Turner wore an incredible embellished golden two piece and jewellery to the wedding reception of Priyanka Chopra and Nick Jonas in New Delhi.

Kendall Jenner rocked a '90s inspired plush velvet gown with a subtle animal pattern on the bodice for the Biebers' romantic bash, accessorised with an equally-nostalgic mini beaded bag.

See the original post on Instagram

Of course Reese Witherspoon attended this Big Little Lies reunion... we mean wedding! Reese wore a floral wrap dress to Zoë Kravitz's wedding reception.

Some of us might panic when we're in the French city of style attending a wedding of someone like Zoë Kravitz. But Cara Delevingne hit the nail on the head in this trim gold tuxedo. We also love Ashley Benson's tan leather mini.

Style icon Sienna Miller paired her Alessandra Rich dress with a diamanté body chain for pal Ellie Goulding's wedding - a trick we are eager to copy to revamp some of our own dresses.

Always elegant and expertly put together, Kate Middleton looked gorgeous in her Alexander McQueen dress with strong shoulders and pleated A-line skirt which she wore to Princess Eugenie's wedding at Windsor Castle.

If you've seen any snaps from Amal and George Clooney's wedding then you'll know Emily Blunt's pale blue floor-length gown fitted in with the glamour perfectly.

As demonstrated in this gallery alone, we can say with certainty that Cara knows how to wear a suit. Her tailored black tails and top hat stood out from the crowd at Eugenie's star-studded nuptials.

Cressida Bonas' unique velvet midnight blue dress looked cracking paired with the jewel tones of her heels and oversized headband at Princess Eugenie and Jack Brooksbank's nuptials.

Naomi Campbell's look at Princess Eugenie's wedding was flawless, including sleek leather gloves, a feather trim dress and gothic floral headpiece.

Pixie Geldof brought a bit of rock'n'roll to Princess Eugenie's royal affair, emulating the likes of Kate Moss, in this bright pink draped dress and shawl finished with a clashing blue clutch bag. Love the red lip too.

Poppy Delevingne's pastel blue coat and lace dress combo complimented her blonde hair and bright red lip perfectly on Princess Eugenie and Jack Brooksbank's wedding day.

Radiant in sunshine yellow and matching hat, Amal Clooney looked incred walking arm-in-arm with George. She appears so relaxed, you'd have no idea she was attending the royal wedding of Harry and Meghan, streamed live to billions of people.

Serena Williams knocked it out the park in her stunning pink structured dress, alongside husband Alexis Ohanian, as they arrived at Meghan and Harry's big day at Windsor Castle.

Carey Mulligan looked ethereal in her suitably British floaty floral tea dress by designer Erdem for Harry and Meghan's special day.

Selena Gomez gave us all the feels when she 'grammed this snap of her Wizards of Waverly Place reunion at TV big bro David Henrie's wedding. The star selected an ankle-length maroon number that we're immediately looking to recreate for our next wedding.

See the original post on Instagram

Here's another one of Princess Diana's best coordinated wedding numbers, smashing the age-old 'rule' that guests can't wear red.

Ah Millie Mackintosh and her never-ending collection of wedding ready dresses. This yellow maxi was from her own fashion collection and suited the stunning scenery perfectly.

See the original post on Instagram

Geri Halliwell selected a blush pink strapless dress for Poppy Delevingne's fancy wedding day.

A royal wedding requires a seriously fancy outfit, which suits Naomi Campbell perfectly.

When Leah Wood and Jack Macdonald got wed, Kate Moss made sure she was looking her best in a silk gown and velvet wrap.

Kim Kardashian wore a plunging LBD to David Grutman's wedding.

Did Kate break the wedding style rules when she wore ivory to Zara Tindall's big day?