Dwayne "The Rock" Johnson has signed on to play one of the earliest superheroes: Doc Savage, who's said to be an inspiration for Superman. A film adaptation of Doc Savage was announced back in 2013, but apparently it's only now getting off the ground. Shane Black, the beloved action movie writer and director of Iron Man 3, is on board to direct.

There aren't many details about the film yet, but Johnson makes it sound like it should be pretty funny and strange. This is what he wrote in an Instagram post announcing the casting (emphasis his): "Here's the #1 reason I'm excited to become Doc Savage... HE'S A F*CKING HILARIOUS WEIRDO!"

Doc Savage is a classic pulp fiction comic hero from the 1930s. The character has no one specific super power; instead, he's supposed to have been groomed by scientists to attain superhuman physical and mental abilities. "His heightened senses are beyond comprehension," Johnson writes. "He can even identify a woman's perfume from half a mile away." Creepy! But I guess it gets the point across.

The character apparently has "zero social graces whatsoever due to his upbringing," Johnson writes, which leads to him being a pretty weird dude. That's what Johnson and Black want to play up in their adaptation.

As Johnson notes in his Instagram post, many elements of Doc Savage are widely recognizable as attributes of Superman. "First name Clark, called 'Man of Bronze,' retreats to his 'Fortress of Solitude' in the Arctic, etc., etc.," he writes.

There's no word yet on when the film is supposed to be released. Johnson suggests that they're still working out the story, so it could be a while longer still.