Coldplay and Cat Power, together on the same track? Certainly anything's possible when you're talking the soundtrack for a Zach Braff movie.
According to NPR, the collaboration came about when Zach sent an early copy of the filmWish I Was Hereto Coldplay so that they could pen the lead single. While writing it, lead singer Chris realized that the song would be better suited for a female vocalist, and it wasn't long before they landed on Chan Marshall (aka Cat Power).
Wish I Was Here will be released on July 18th, while the soundtrack will come out a few days before (on the 15th). If you're keen, you can pre-order it here.