Kacey Musgraves gave fans a major special treat during the final stop of her Oh, What a World: Tour II: Harry Styles! The one-time boyband star stopped by Bridgestone Arena on Friday (Oct. 25) to surprise Musgraves' crowd of 18,373 — an attendance record at the Nashville venue.

"It feels like one gigantic victory lap of sorts," the "Rainbow" singer told the crowd, according to the Tennessean. "And I'm just so happy that I'm in Nashville, and we're all together. I've got family in the house. All my friends are here. So many people in this community that I look up to and just admire. And of course, I could never have had this much love and positivity coming out with this record without you guys."

Musgraves welcomed the One Direction-singer-turned-solo-artist onto her stage, and fans erupted with excitement that the tourmates were reuniting. Styles let out a yee-haw when he walked out and began to sing one of Musgraves' most popular and Grammy award-winning songs, "Space Cowboy."

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"As a peer, and someone I like to call a friend, it’s always a pleasure, an honor to share the stage with this lady," Styles told the crowd, according to Rolling Stone. "She’s made a couple of my favorite albums, and it’s an honor to be here tonight with all of you to say congratulations and round off this wonderful tour, and a wonderful year."

Musgraves was a supporting act for Styles' 2018 tour, and the pair frequently covered Shania Twain's classic, "You're Still The One," live, so there was some familiarity in their "Space Cowboy" duet.

Though Musgraves' tour has wrapped,, she is set to perform at Las Vegas' Intersect Festival on Dec. 6 before a string of international dates in early 2020.

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