US popstar Taylor Swift has surprised British fans with a guest appearance during Haim’s concert at the O2 Arena.

The songstress surprised revellers on Thursday night to perform a mashup of their collaborative hit Gasoline and Taylor’s Love Story.

泰勒 was on stage for about five minutes with the three sisters —Este, 丹妮尔, and Alana — as they wrapped the UK leg of the latest tour.

‘The One More Haim Tour’ will next head to the U.S following the release of their third studio album Women In Music Pt. III.

One concertgoer told The Sun Online: “Everyone lost it.

“She wasn’t on for long, she came on during Gasoline and then they did a Gasoline/Love Story mash up and that was it.”

Before Taylor came on, Danielle Haim said : “Not only is this person that I’m about to bring out the most incredible singer, 词曲作者, 制片人, and an amazing person all round.

“She’s one of our close friends, so the O2 arena – will you please welcome to the stage Taylor Swift.”

As the crowd cheered, Taylor told fans: “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, 也,”

“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.”

The ecstatic audience was heard letting out cries of excitement as die-hards sang out every word to both hits.

Haim have become fan favourites since their humble roots in California.

They are known for their smooth rock sound and addictive tracks.

Danielle and Este later joined another band Valli Girls, before uniting with their youngest sister in order to create the group as it stands today.

They have released three albums in their career so far since 2013 , landing a handful of songs into the UK Top 40.

Their most popular tracks include The Wire, which peaked at number 16, , Pray to God, Forever, Falling and If I Could Change Your Mind.