Keith Urban played two back-to-back shows at the Grand Ole Opry on Tuesday night (Oct. 10), and the audience got much more than they expected.

The "Blue Ain't Your Color" singer offered a last minute surprise guest in the form of Chris Janson during his two-show run at the iconic Nashville venue. Janson joined Urban onstage for an energetic cover of John Michael Montgomery’s “Sold (Grundy County Auction).”

The two country artists both both got their start playing in country cover bands, so they both knew Montgomery's 1995 No. 1 song well. Still, they rehearsed on the tour bus first, and Urban shared that fun video with fans. Both jam out on their guitars in the clip, trading verses and coming together at the chorus. But when Janson takes out his harmonica, it's all over for Urban, who erupts in laugher.

"Thanks @KeithUrban for this incredible @opry moment! You are a class act all the way and I love you. #grundycountyauction," Janson wrote on Twitter.

Urban's “Blue Ain’t Your Color” is nominated for Video of the Year, Single of the Year and Song of the Year at the upcoming 2017 CMA Awards, which are set to air on Nov. 8 on ABC.

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