Dolph Lundgren has joined Warner Bros. standalone “Aquaman” film opposite Jason Momoa, sources have confirmed to Variety.

Lundgren will play King Nereus of the aquatic kingdom of Xebel, who claims Aquaman’s wife Mera (Amber Heard) as his own and wants to kill him. The cast also includes Nicole Kidman, Willem Dafoe, Patrick Wilson, and Yahya Abdul-Mateen II as Black Manta.

James Wan is directing the superhero film with Peter Safran producing. Deborah Snyder, Zack Snyder, and Rob Cowan are executive producing.

The studio said last year that the title character, played by Momoa, would be caught between a surface world constantly ravaging the sea and the undersea Atlanteans, who are ready to lash out in revolt. Aquaman is based on the DC Comics character first introduced in the early 1940s who’s the king of Atlantis — a half-human and half-Atlantean named Arthur Curry.

Lundgren was an ’80s and ’90s action star whose credits included “Universal Soldier,” “The Punisher,” “Masters of the Universe,” where he played He-Man and “Rocky IV.” Lundgren took a break from acting but has recently made a comeback with “The Expendables” franchise.

The Swedish actor is repped by Gersh.