Momoa has been teasing the role, and most recently director Zack Snyder defended the character on air to a Detroit radio station.
Jason Momoa joins Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, with Ray Fisher also rumored as Cyborg.
"Batman v Superman: Dawn of Justice" has a March 25, 2016 release also starring Amy Adams as Lois Lane, Laurence Fishburne as Perry White, Diane Lane as Martha Kent, Jeremy Irons as Alfred, Jesse Eisenberg as Lex Luthor, with Callan Mulvey, Holly Hunter and Tao Okamoto in new character roles for the film. Justice League is to follow directed by Zack Snyder as well.
For more news on the "Man of Steel" and related movies head on over to the Cosmic Book News Superman movie hub.