Chris Stapleton has been touring with Miranda Lambert's boyfriend, Anderson East, on his All-American Road Show, and on Sunday night (July 16), Lambert tagged along to the show, too. During Stapleton's headlining set, the country superstar made a surprise appearance onstage to help sing Stapleton's song "Fire Away."

At Stapleton's show in Buffalo, N.Y., Lambert casually strolled onto the stage prior to the start of "Fire Away;" the crowd quickly caught on, greeting her with loud cheers as Stapleton's wife Morgane welcomed her. The two women added harmonies throughout "Fire Away," with fans singing and cheering along, but near the end of the song, the Stapletons ceded lead vocals to Lambert. The audience roared with approval as Lambert finished off the tune, earning a hug from Morgane Stapleton and words of praise from Chris Stapleton.

Her Sunday night performance was not Lambert's first time sharing the stage with Stapleton: During a show in April of 2016, both Lambert and East joined Stapleton and his wife onstage to sing the classic song "My Girl." Lambert has also performed with East at some of his shows as well.

Stapleton's All-American Road Show is keeping him busy on the road this summer, though a few stops on the trek had to be postponed, from June until later in 2017, due to a hand injury that Stapleton suffered in late May. In addition to East, the Brothers OsborneLucie SilvasBrent Cobb and Margo Price are all acting as special guests on the tour. Cobb and East both played with Stapleton at Sunday night's show; Stapleton also shared a brand-new song, "Trying to Untangle My Mind," during the concert.

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