Taylor Swift Performs a Surprise Mashup With Haim in London: Would You Join Us in Singing?

Taylor Swift joined Este, Danielle and Alana Haim to sing a mashup of the foursome's remixed track "Gasoline" and her own song "Love Story"

When Haim and Taylor Swift reunited on stage for a special mashup on Thursday night, they delivered fans an amazing surprise

The trio of sisters hauled up their buddy to surprise fans when they performed at the O2 Arena in London as part of their One More Haim Tour

"All Too Well" singer, 32, joined Este, Danielle and Alana Haim to sing a mashup of the foursome's remixed track "Gasoline" and Swift's "Love Story."

"When I learned that my daughters were performing at the O2 in London, I was excited

'I'm gonna have to see that.' And it looks like there's about 20,000 other people that also thought that," Swift said as she took the stage

We had a thought, that if we were to do some sort of mashup, we could possibly maybe get you to sing the loudest that you have sung all night