Ashley Monroe's The Blade album release party had its fair share of special guests: Vince Gill (who co-produced Monroe's new record) and Striking Matches joined the singer during her performance, and according to Taste of Country, Nashville's Sam Palladio, Little Big Town's Phillip Sweet and Meghan Linsey were all in the audience. But one of the evening's biggest guest appearances came during the encore, when Monroe brought Miranda Lambert out to perform "Heart Like Mine."

Lambert's surprise appearance at the Wednesday night (July 22) event at the Basement in Nashville was her first since the announcement of her divorce from former husband Blake Shelton. She and Monroe told the crowd that they hadn't rehearsed "Heart Like Mine," but it didn't matter; they sounded on point and traded lines flawlessly (all that time singing together in the Pistol Annies probably helped!), and received a rousing round of applause. Press play on the video above to watch a snippet of the performance.

The two friends co-wrote "Heart Like Mine," along with Travis Howard, for Lambert's 2009 Revolution album. They join together again on The Blade, duetting on the album's title track, which was written by Marc Beeson, Jamie Floyd and Allen Shamblin. Lambert did not join Monroe to perform that tune during the album release party.

On July 28, Lambert will be playing her own Nashville club show, at Music City's 3rd and Lindsley. The acoustic event will include performances by former The Voice contestant RaeLynn, as well as Clare Dunn, Courtney Cole and songwriters Natalie Hemby and Jessi Alexander. Tickets went on sale on Monday morning and sold out in less than two minutes.

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