Taylor Swift Crashed Haim's London Concert For A "Love Story" Mashup

Taylor Swift surprised fans by joining her pals Haim at their London show on Thursday night, for a mashup of “Love Story” and “Gasoline.” (Swift made a remix of Women in Music Pt. III track “Gasoline” with Haim last year, but up until now, it’s never been performed live).

The artists go way back, with the sister trio performing as the opening act of Swift’s 2015 1989 tour. This time around, Haim was headlining London’s O2 Arena — and given Swift’s current connection to the city via boyfriend (and “London Boy” inspiration) Joe Alwyn, it makes sense that she was in town. Haim are currently on their Women In Music Pt. III tour, which wraps this October in California. It’s been a big year for Alana Haim in particular, as she starred in her breakout role in the Oscar-nominated Licorice Pizza.

Swift and Haim all wore matching black leather pants with black crop and bra tops for the blazing hot night. The singer revved up the crowd before leading a sing-along mashup of her Fearless hit “Love Story” and the aforementioned “Gasoline.” See fan videos of the moment, below: