Jason Momoa, who played Conan the Barbarian in an ill-fated attempt to revive the classic Robert E. Howard franchise and the barbarian leader Khal Drogo in the current season of the much more successful fantasy Game of Thrones, will take on the role of Aquaman in a series of Warner Bros. movies based on DC Comics. 

Momoa will appear first in Batman v. Superman: Dawn of Justice, which Zack Snyder is currently preparing for a May, 2016 debut.  It is expected that Momoa’s Aquaman will play a much larger role in the Justice League movie that will be shot back-to-back with Dawn of Justice, and which appears to be slated for a May, 2017 release (see "Warners' DC Film Schedule"). 
Rumors connecting Momoa to the Batman v. Superman project first appeared last December (see "Jason Momoa in 'Batman/Superman'"), but stories indicating that the hulking star would play Aquaman are of a more recent vintage. 
The Hollywood Reporter cited inside "sources" to confirm the story that Momoa would play Aquaman that was first reported by HitFix.