Back in February, Dwayne Johnson revealed that production will begin on Rampage in April, while sharing that his character is a "Primatologist" who serves as the head of an anti poaching unit in Rwanda. Since then, the cast has started to come together, with Naomie Harris playing a geneticist who teams up with Dwayne Johnson's character, and Malin Akerman portraying the villain, the head of the corporation responsible for creating the three monsters seen in the film. Today we have word that the cast has gotten even bigger, with The Walking Dead star Jeffrey Dean Morgan signing on.

Deadline reports that Jeffrey Dean Morgan will portray Agent Russell, who works for a secret government agency known as OGA, with the character described as someone who, "rolls with serious swagger and attitude." It isn't known if he has any connection to Dwayne Johnson's character or not. Regardless, he joins a cast that also includes Joe Manganiello, Jake Lacy, Marley Shelton, PJ Byrne, Jack Quaid, Matt Gerald and Breanne Hill. While Jake Lacy is playing the brother of Malin Akerman's villainous character, no details have been given about the rest of the characters, or how many more roles are needed to be filled.

Dwayne Johnson's character has also been described as an "animal-loving hero" who is the only one who can stop these massive monsters from destroying the world. The original Midway video game allowed players to control three monsters, an enormous lizard named Lizzie, a giant werewolf named Ralph and a massive ape named George. Players used these enormous monsters to completely destroy a number of different cities around the world, although it hasn't been confirmed if the movie adaptation will be a globe-trotting adventure, with these monsters destroying city after city, or if it will be confined to one particular location.

Related: Rampage Review: The Rock Delivers a Giant Monster Carnival of Fun

Brad Peyton is directing Rampage from a script by Carlton Cuse, Ryan Condal and Ryan Engle. Beau Flynn is producing alongside John Rickard of Wrigley Pictures, Hiram Garcia from Dwayne Johnson's 7 Bucks Entertainment, and Brad Peyton. Wendy Jacobson of Flynn Picture Co. is co-producing. Marcus Viscidi, Dwayne Johnson, Dany Garcia and Jeffrey Fierson are exec producing. New Line has already handed out an April 20, 2018 release date for The Rock's new movie Rampage, which will go up against Universal's comedy The Pact.

This project reunites The Rock with Brad Peyton and Beau Flynn after collaborating on hits such as Journey 2: The Mysterious Island, Hercules and San Andreas. Jeffrey Dean Morgan is coming off his first full season as the iconic villain Negan in AMC's hit zombie series The Walking Dead, after his character was introduced in the Season 6 finale. He will be returning for Season 8, and he was last seen on the big screen in an uncredited role as Thomas Wayne in Batman v Superman: Dawn of Justice, and in the indie thriller Desierto. With production starting soon on Rampage, hopefully we'll hear more about the growing cast and the story soon.