Kacey Musgraves is having a ball on her “Middle of Nowhere” tour.

The singer had fans in disbelief when she unveiled an X-rated prop Friday, as she kicked off her tour at the United Center in Chicago. Musgraves sat on giant bedazzled disco balls shaped like testicles.

Fittingly, she brought out the disco balls while singing her song “Rhinestoned.”

Musgraves sat in a seat in the middle of the shiny balls, which were suspended above the air. She looked completely comfortable as she performed, wearing a white tank-top, jeans and a cowboy hat.

She had fun with the moment, posting a clip on her Instagram Stories of herself on stage when the massive prop dropped down.

“It takes a lot of balls to get up and do what I do every night,” she said as her fans clapped. “It takes two gigantic, anatomically-correct sparkling balls, in fact.”

She also shared her grandmother was at her performance.

“I’ve actually got my nana in the house tonight,” she said. “You know, she always told me, ‘Honey, if your’e gonna do something, do it big and do it sparkly.’”

“Nana, is this what you had in mind?”

Musgraves turned 37 years old Friday. She poked fun at her age with fans, re-posting an Instagram Story of herself joking on stage that she’s a “geriatric millennial.”

She also re-posted a sweet birthday message from Reese Witherspoon reading, “Happy birthday to my mystical, lyrical, space cowgirl! Love you and your intergalactic spirit.”

The “Rainbow” singer’s tour runs until Feb. 26, with the last stop being at the OVO Arena Wembley in London.

Last month, fans were shocked when she quietly nixed three of her “Middle of Nowhere” tour dates — including opening night — just weeks before she was set to hit the road.

According to the Daily Mail, she quietly cleared three shows — opening night in Chicago which was supposed to be on Aug. 20, a Boston show on Aug. 29 and a Brooklyn performance on Sept. 2 — with fans only receiving a Ticketmaster email informing them of the cancelations.

No explanation was given for the canceled shows.