Action man Dwayne Johnson has been cast as comic book villain Black Adam in the upcoming Shazam blockbuster.

The Hercules star has been hinting about a role in the superhero film for several months and on Wednesday (03Sep14) Johnson revealed he will play the bad guy.

In a message on Twitter.com, he writes,"'Kneel at his feet or get crushed by his boot'. My honor to become.. #BlackAdam #TheAntiHero #DCComics."

Details surrounding the film have yet to be released, but Shrek Forever After's Darren Lemke is reportedly writing the script, while Hiram Garcia will produce with Johnson, according to Variety.com.