The musical mind behind the "Cha Cha Slide" — the ubiquitous turn-of-the-millennium dance hit played at celebrations and in gyms across the world — has died.

DJ Casper died Monday after a long battle with cancer, his wife told ABC7 in Chicago. He was 58.

Born Willie Perry Jr., the Chicago native originally recorded a version of the "Cha Cha Slide" in the late 1990s as an aerobic exercise for his nephew, who was working as a personal trainer at Bally Total Fitness.

Casper said the track quickly took off and he got requests to perform it at local clubs and parties, according to WBEZ. Chicago's WGCI-FM radio station aired the song in 2000 before it was eventually picked up by Universal Records.

"I really didn't expect the 'Cha Cha Slide' to do what it did," Casper said in an interview with Chicago's PBS station WTTW in 2018. "Everything hit all at once, Universal Records contact me, they wanted me to go on a tour and it started getting real crazy."

According to Pitchfork, Casper composed a new version that year initially called "Casper Slide Part 2," which became the "Cha Cha Slide" that caught fire in the U.S. and hit No. 1 on the charts in the United Kingdom in 2004.

From humble workout track to global phenomenon, the "Cha Cha Slide" endures to this day as a staple at weddings, birthday parties, school phys ed classes and more.

In the song, Casper calls out easy-to-follow steps that invite dancers to slide to the left and right, criss cross, Charlie Brown and — of course — cha cha real smooth.

Now a pop culture mainstay, the "Cha Cha Slide" has stomped its way into shows like Orange is the New Black and Saturday Night Live.

Casper told ABC7 that he was diagnosed with kidney and liver cancers in 2016 and lost about 60 pounds as a result, but he never lost the upbeat attitude that pervaded his most famous song.

"Anybody that's going through cancer, know that you have cancer and cancer does not have you," Casper told the station. "So, keep on doing the 'Cha Cha Slide.' "