Taylor Swift thrilled the audience at Haim's concert in London on Thursday night by joining the trio onstage for a surprise mash-up.
The crowd at London's O2 Arena went wild when Alana Haim invited the band's close friend onto the stage to perform their hit Gasoline.
Midway through the performance, Taylor said to the audience, "Good evening London. You know, I haven't been on the stage for a very long time, it's nice, it's nice, it's very nice. But, you know, when I heard that my girls were playing in London at the O2 and I thought, 'I'm gonna have to see that' and it looks like there's about 20,000 other people that also thought that."
Taylor, who hasn't been on tour since 2018, then teased a mash-up, adding, "We had a thought - that if we were to do some sort of mash-up, we could possibly maybe get you to sing the loudest that you have sung all night, which is a big job because you've been singing very loudly, it's extraordinary work. Would you be up for it? Would you sing with us?"
Alana, Este and Danielle Haim continued to play the music for Gasoline as Taylor sang a snippet of her 2008 smash hit Love Story before circling back to Gasoline.
At the end of the performance, Taylor saluted the audience and said, "Ladies and gentlemen, please take care of my best friends for the rest of the evening. Thanks for having me, good evening."
The Haim sisters all ran over to hug Taylor before she left the stage.
The pop star coordinated outfits with the siblings by wearing the same custom Louis Vuitton leather trousers that they've worn throughout the tour. However, she wore a black crop top instead of the sisters' bikini tops.
Joking about stealing their look on TikTok, Taylor wrote, "Hitting copypaste on your friends' looks like @haimtheband."
The Shake It Off singer has been close friends with the group for years. She appears on a remix of Gasoline, which was released as a single in February 2021. Haim previously collaborated with Taylor on No Body, No Crime from her 2020 album Evermore.