Have tickets to one of the few upcoming George Strait and Reba McEntire concerts? You just may get Kelly Clarkson as well.

At a series of shows last week in Pittsburgh, Philadelphia and Buffalo, N.Y., the Season 1 American Idol winner was Reba’s surprise guest, joining the reigning queen of country music onstage to wow audiences with her own powerful voice.

At Friday’s (Oct. 15) performance in Philly, a barefoot Kelly sang a trio of songs with her mentor and friend: her own “Walk Away,” Reba’s “Why Haven’t I Heard from You,” and, of course, the duo’s shared hit “Because of You,” which appeared on Reba’s Duets album.

But Kelly wasn’t the only cameo. Tour opener Lee Ann Womack also joined the red-headed Oklahoman for a playful face-off on “Does He Love You.” And a beaming Reba was clearly thrilled. “I love singing with my buddies!” she exclaimed.