Kacey Musgraves launched her "Middle of Nowhere" tour in Chicago on Friday, debuting a provocative stage prop that drew gasps and cheers from the audience. The Grammy-winning singer performed atop a set of giant, bedazzled disco balls humorously shaped like testicles.

The eye-catching element was revealed as Musgraves performed her song "Rhinestoned" at the United Center. She was seated in a chair suspended mid-air within the large, glittering orbs.

Musgraves engaged with the unexpected prop, joking with the crowd, "It takes a lot of balls to get up and do what I do every night." She added, "It takes two gigantic, anatomically-correct sparkling balls, in fact."

The singer also shared a personal moment, noting her grandmother was in attendance. "Nana, is this what you had in mind?" she quipped, referencing her grandmother's advice to "do it big and do it sparkly."

Musgraves celebrated her 38th birthday on the same day as the tour's opening night. She playfully referred to herself as a "geriatric millennial" on stage and acknowledged a birthday message from Reese Witherspoon, who called her a "mystical, lyrical, space cowgirl."

The "Middle of Nowhere" tour is scheduled to run until February 26, concluding with a performance in London.

Last month, Musgraves quietly canceled three dates on the "Middle of Nowhere" tour, including the originally scheduled opening night in Chicago, without providing an explanation.