Brandi Carlile stunned the Bonnaroo Festival audience on Sunday (June 16) with a surprise guest—Tanya Tucker!

Almost halfway through Carlile's set, the singer began speaking about Tucker's comeback to music and her release of a new album for the first time in 17 years, before the legend came out to join her on stage.

Carlile told the crowd that Tucker is "the most punk-rock country singer to ever live," and further declared her "Tanya Mother Tucker."

The pair sang Tucker's current single "Wheels of Laredo," off Tucker's upcoming album While I'm Living, to roaring approval from the audience. Tucker even brought out her Cosa Salvaje brand of tequila so the pair could share a toast.

Tucker's forthcoming album is being produced by Carlile; Shooter Jennings joins them to co-produce a few songs as well.

Carlile was busy at this year's Bonnaroo as both a fan and performer. She treated audiences on Saturday (June 15) with guest performances alongside John Prine and Hozier during each of their respective sets.

Tucker and Carlile also performed Tucker's hit "Delta Dawn" at the CMT Awards alongside women of country including Martina McBrideTrisha YearwoodLauren AlainaDeana CarterRaeLynn and Carly Pearce.

Who Is Brandi Carlile?