Director Patty Jenkins and DC Entertainment President & Chief Creative Officer Geoff Johns have been writing the treatment for the 2019 Wonder Woman sequel since June, with news of Johns' involvement confirmed just one month later. Now, Johns and Jenkins will be joined by The Expendables scribe Dave Callaham.

According to The Hollywood Reporter, Jenkins and Callaham worked together on Jackpot, which led Jenkins to bring him on board for Wonder Woman 2. In addition to the ensemble action franchise, Callaham's writing credits include Doom and 2014's Godzilla. He has also been announced for features such as Zombieland 2 and the Simon McQuoid-directed Mortal Kombat.

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News of Callaham's involvement comes hot on the heels of the news that Patty Jenkins has officially signed on to direct Wonder Woman 2. While Jenkins, Johns and others have remained relatively tight-lipped about the premise of the film, Jenkins did promise that fans can expect to see a "fully-blown" Wonder Woman this time around.

“The greatest thing about making this movie was the fact that you’re really building to the Wonder Woman that we all love, but not until the end of the movie,” Jenkins said at the time. “The most exciting thing about [the sequel] is literally seeing her loose in the world now, living those classic stories. Here’s Wonder Woman, and what can she do? It should be a totally different movie, but a grand and now full-blown Wonder Woman in the world.”

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Wonder Woman is still gathering a lot of attention, recently crossing $800 million worldwide and gathering Oscar buzz for Best Picture and Best Director. “It’s wonderful, it’s what you hope for,” Jenkins said of the film’s success. “You work so hard on [films] for so long, everybody that makes them hopes for success in every way they can possibly get it. So it’s felt very lucky and incredible to get both.”

Wonder Woman 2 will hit theaters on December 13, 2019, but Gadot's Amazon Princess will be seen next in Zack Snyder's Justice League, which also stars stars Ben Affleck as Batman, Henry Cavill as Superman, Amy Adams as Lois Lane, Jason Momoa as Aquaman, Ezra Miller as The Flash, Ray Fisher as Cyborg, Willem Dafoe as Vulko, Jesse Eisenberg as Lex Luthor, Jeremy Irons as Alfred Pennyworth, Diane Lane as Martha Kent, Connie Nielsen as Queen Hippolyta and J. K. Simmons as Commissioner Gordon. Justice League hits theaters November 17.