Ed Sheeran and Taylor Swift wrote their song on a trampoline

Sheeran told Rolling Stone that the writing session took place at Swift's house and was "very fun".

"We wrote a song on a trampoline, ate some apple pie and had a jam," he revealed.

"It came in 20 minutes, really. It was a really simple song to write. We just had two guitars and strummed it out. I've heard from everyone in the industry how cool she is; she's got a very good reputation, but you never really realize what kind of person she is until you sit down and chat with her. She's just a very warm soul."

He told the magazine that the collaboration happened when Swift's management turned up at one of his gigs in Nashville, a couple of days after which he received an email from the country darling herself asking if he'd like to write a song together.

"We hooked up and wrote two tunes, actually, one on the record and another that's still out in the ether somewhere," he said.

The first tune will appear on Swift's upcoming album, Red - let's hope we get to hear the second sometime, too!