Dolph Lundgren is ready to “break” Aquaman.

The legendary action star is set to join Jason Momoa, Amber Heard, and Patrick Wilson in Aquaman, but he will not be an ally of the King of Atlantis, according to The Hollywood Reporter.

Lundgren is set to play King Nereus, who rules the kingdom of Xebel and wants to take down Aquaman. But that’s not all: Nereus also thinks he has the right to be with Mera (Heard), Aquaman’s love interest. So yeah, Lundgren should definitely have a fight or two with Momoa—who got himself absolutely shredded to play the hero—during the course of this film.

The swashbuckling, deep ocean-set movie is expected to be a stylistic departure for the DC movie universe, and that might be its best asset. Director James Wan comes over from the Fast & Furious franchise, and he was excited to welcome Lundgren’s “not quite villain” to the fold:

Even though Wan describes the role as “not quite” a bad guy, based on the reported run down of the character, he’s going to have some friction with Aquaman no matter what side he’s on. Perhaps, like Donnie Yen in xXx: The Return of Xander Cage, he’ll start out as a rival/unfriendly foe to the main hero before turning around and hepling him out by the movie’s end.

The rest of the cast includes Wilson, who’s playing Orm (a.k.a Ocean Master), the main villain and Aquaman’s half-brother; while Nicole Kidman stars as Aquaman’s mother; Willem Dafoe is set as Aquaman’s adviser, scientist Dr. Vulko; and Yahya Abdul-Mateen II is playing villain Black Manta.

Lundgren knows a thing or two about being a villain, or at least a semi-bad guy.

Even though he’s pushing 60, Lundgren is showing no signs of slowing down in his career. The actor signed onto CIA action thriller Black Water, in which he’ll star alongside fellow ‘80s action legend Jean-Claude Van Damme. Lundgren also could appear in a potential Expendables 4 movie, but if his buddy Sylvester Stallone bails out, he could follow in the footsteps of Arnold Schwarzenegger and leave the series, too.

Either way, Aquaman just added a bunch more muscle.

Aquaman will be released on December 21, 2018.