The Aquaman lineup is finally complete.

Even though news broke in February that actor Yahya Abdul-Mateen II would star in Aquaman as the villain Black Manta—he's also in Baywatch—the news hadn’t been confirmed by the actor himself. But with one response on Twitter to Dwayne “The Rock” Johnson, Abdul-Mateen officially got the chance to reveal his role as a nemesis to Aquaman himself, aka Jason Momoa.

Johnson previously welcomed Abdul-Mateen “to the club”—The Rock is set to play Black Adam in his own DC film—and Abdul-Mateen was “finally” able to return the favor:

 

 

Although the news wasn’t official until April, it didn’t stop Abdul-Mateen from getting started on his training.

To go up against the absolutely shredded Momoawho is as grizzly and badass a man as there is in Hollywood—Abdul-Mateen got into the gym and started beefing up:

 

 

Pick up heavy sh*t. Put it down. Do that sh*t again. @fitnessbyfortitude

A post shared by Yahya Abdul-Mateen II | Actor (@yahya) on

 

The Black Manta character has a long and wild comic book history with Aquaman, first appearing in 1967 and possessing a range of powers and abilities, including enhanced strength, a high-tech battle suit that can shoot optic blasts, and expertise in hand-to-hand combat.

Abdul-Mateen’s villain will be just one of the foes that Momoa will have to face: Hero Arthur Curry will also go up against Ocean Master (Patrick Wilson), his half-brother and rival. The cast is rounded out by Amber Heard as Mera, Aquaman’s kick-ass love interest; Willem Dafoe as Vulko, a scientist and Aquaman’s advisor; and Nicole Kidman as Queen Atlanna, Aquaman’s mother.

Aquaman, directed by James Wan, will be released on December 21, 2018.