What group performs the version of Angel Band not found on soundtrack at end movie O Brother Where Art Thou just before credits begin?

The version of "Angel Band" that plays at the end of *O Brother, Where Art Thou?* before the credits, and is not on the soundtrack album, is performed by The Fairfield Four.

This version is a more traditional gospel rendition compared to the more bluesy version on the album, which is performed by the film's fictional group, the Soggy Bottom Boys.