Here's some exciting news to sustain Swifties through the long holiday weekend: Taylor Swift will debut a brand-new song next week!

'Sweeter Than Fiction,' a "poppy" tune Taylor co-wrote with fun. guitar player Jack Antonoff, is set to appear on the soundtrack of upcoming film 'One Chance.' She is expected to perform the song live during the movie's Sept. 6 premiere at the Toronto International Film Festival.

The movie's plot follows the story of a small-town steel worker's rise to fame following an appearance on 'Britain's Got Talent.' 'Sweeter Than Fiction' plays during the film's end credits.

Producer Harvey Weinstein credits Simon Cowell, of all people, for getting Swift involved in the project. "Simon knows her through the One Direction connection and he thought she'd be touched by the film, and he was right because she was," Weinstein says.

A Taylor collabo with a member of fun.? FUN!