The Mission: Impossible star will play Stacee Jaxx in the film, and belt out Bon Jovi's Wanted Dead or Alive.
Matt Weaver, who co-created Rock of Ages, is thrilled with the casting: "He's got an awesome voice! He's got an awesome attitude.
"He's embracing it, he's getting into character, he's doing his research. He's ready to go back to 1986!"
Julianne Hough, Alec Baldwin, Anne Hathaway and Russell Brand are also reportedly in talks to join the cast.
Hough was among the stars who attended the opening night of the hit musical's run in Los Angeles on Tuesday (15Feb11). Zac Efron, Malin Akerman, Shannon Elizabeth, Carmen Electra and Mena Suvari were among the audience.