Credit: Jeff Kravitz/FilmMagic

What did Katie Holmes think of Tom Cruise's hip-shaking, hip-hop performance with Jennifer Lopez at Sunday's MTV Movie Awards?

"She loved it!" Cruise, 47, told UsMagazine.com backstage. "She was there while we were working on it... it was a blast!"

Reprising his role as Les Grossman from Tropic Thunder, Cruise jokingly tried to smack Lopez's booty (after she smacked his) during the performance -- but she wouldn't let him.

How did he master the moves? With help from his wife's choreographer, Tyce Diorio.

"I can dance a bit," Cruise told Us. "My wife's a dancer, so I like dancing."

Cruise is no stranger to the world of dance. Just last month, Cruise teamed up with Holmes to perform "Whatever Lola Wants" at a charity event.