Toward the end of the show, Musgraves brought out Styles to help sing her gorgeous song "Space Cowboy," from 2018's Golden Hour. The crowd, of course, loved every minute of the surprise duet.
"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 roaring audience, the Tennessean reports. "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."
This isn't the first time Musgraves and Styles have performed together on stage. Last year, while the country songstress was opening on Styes' North American arena tour, the pair joined forces in New York for a swoon-worthy cover of Shania Twain's "You're Still the One."
At the time, Styles introduced the tune as one of his "personal favorites" and encouraged the arena to sing along, which they did as soon as Musgraves began the ballad.
Meanwhile, Musgraves announced on Twitter Friday that her Nashville concert "broke an attendance record" for a female headliner at Bridgestone Arena, with 18,373 fans in attendance.