Swift released folklore in July, and worked on the album remotely during lockdown with The National's Aaron Dessner, Jack Antonoff and Bon Iver's Justin Vernon.

The full credits for folklore also revealed that Bon Iver collaboration "exile" and "betty" were both co-written with someone called William Bowery. Fans have been speculating over who Bowery is, and in her new folklore: the long pond studio sessions concert film released earlier today (25 November) Swift confirmed that Bowery isn't a real person.

Swift did reveal during the film that William Bowery is in fact her boyfriend and actor Joe Alwyn. She said, "There's been a lot of discussion about William Bowery and his identity because it's not a real person. William Bowery is Joe, as we know."

The folklore singer went on to explain Alwyn's roles on the tracks to co-producers Aaron Dessner and Jack Antonnoff, "Joe plays piano beautifully. He's always just playing and making things up and kind of creating things. And "Exile" was crazy because Joe had written that entire piano part."

Swift continued, "He was singing the Bon Iver part, and so I was entranced and asked if we could keep writing that one. It was pretty obvious that it should be a duet."

Taylor Swift's folklore: the long pond studio sessions film is available to watch on Disney+ now.