The actor and his wife, Brooke Mueller, are expecting their first child together. There's no word yet on a due date.
"Brooke and I are thrilled! She's the best stepmom Sam, Lola and Cassandra could ever hope for," Sheen tells Us Weekly. "Seeing her love and affection with those three, I know she'll be an amazing mom."
Sam, 4, and Lola, 2, are Sheen's daughters with ex-wife Denise Richards. Cassandra, 23, is his daughter with former girlfriend Paula Profitt. Sheen adds, "Unless I bat 100%, perhaps a boy awaits us."
The 42-year-old Sheen and Mueller, 30, were introduced at a charity event in 2006 (by "Grey's Anatomy" star Eric Dane and his wife, actress Rebecca Gayheart). He proposed last year, and they married in a small ceremony in Los Angeles on May 30.