Kenny Chesney and singer-songwriter Matraca Berg made surprise appearances when Grace Potter & the Nocturnals performed "You and Tequila" during their Monday night (Sept. 12) concert at Nashville's Ryman Auditorium. Earlier in the show, Potter told the crowd Chesney was not there. Before performing the duet Chesney and Potter recorded for his latest album, Hemingway's Whiskey, Nocturnals guitarist Scott Tournet said he felt nervous and uncomfortable as the country star's substitute at a venue as prestigious as the Ryman. Chensey then walked onstage to sing the song with Potter, and Berg, who co-wrote the song with Deana Carter, also showed up to provide background vocals. The Chesney-Potter collaboration is currently No. 4 on Billboard's country songs chart. She and her band also performed Sunday night at the Ryman. Chesney made a similar surprise appearance in October 2010 when Grace Potter & the Nocturnals appeared at the Ryman as the Avett Brothers' opening act.