'Dancing With the Stars' Season 21: Gary Busey Joins the Celebrity Cast The actor will join the likes of Bindi Irwin and Nick Carter for season 21.

 -- Gary Busey is joining the cast of "Dancing with the Stars."

The actor will appear in the show's 21st season, he revealed Tuesday on "Jimmy Kimmel Live."

Busey entered the studio riding a horse, drawing cheers from the audience. Kimmel asked him why he decided to join "Dancing with the Stars" now.

"I didn't have anything else to do," he said.

Busey, 71, is the ninth competitor to be announced. Bindi Irwin, Victor Espinoza, Nick Carter, Hayes Grier, Alexa and Carlos PenaVega, Chaka Khan and Andy Grammer will also be competing on the ABC show.

In the past few years, the actor has been hard at work, appearing in films such as "Entourage" and "Behaving Badly," and TV shows including the UK version of "Celebrity Big Brother," "American Dad!" and "Two and a Half Men."

Watch “Good Morning America” 7 to 9 a.m. ET Wednesday, Sept. 2 to see the full cast revealed!