Jason Momoa. Picture: Warner Bros

American star Jason Momoa is "pretty much naked" for half of 'Aquaman', according to director James Wan.

The 41-year-old director has hailed Zack Snyder's decision to cast the muscular actor as Aquaman, saying his "physicality" is perfect for the role in the upcoming DC movie.

He confessed: "He's pretty much naked half the movie."

James claimed that Jason's enviable physique will mean that Aquaman is no longer the figure of fun he's previously been, especially compared to some other superheroes.

He told JoBlo: "That's what makes him so cool, right, just his physicality, right? And I think ... I've gotta say, this is a stroke of genius on Zack's behalf, right? 

"This is Zack's casting. He saw something in Jason and he'd go, 'You know what? If I put Jason in this, no one's ever gonna make fun of Aquaman ever again.' And I think that's super great. That's really cool. It's not easy. Jason works very hard to stay in shape and he's very disciplined about it."

James also revealed the movie will have an optimistic tone, like the critically-acclaimed 'Wonder Woman' film that was released in 2017.

He said: "I feel like the good thing about having something that isn't really established is I get the opportunity to set the world, set the tone, set the flavour for who this guy is and the world that he lives in. 

"That's what we love about superheroes, right? We love that they represent the best part of who we want to be, right, what we strive for and what we aspire to be. And I think what I like most about this character and actually what Jason Momoa brings to it is the idea that this isn't a ... that here is a guy who's kind of trapped between two worlds. He's not ... he doesn't feel like he belongs in the surface world but he doesn't feel like he belongs in the world of Atlantis as well, the underwater world. 

"And so I think that's a really interesting ... it gives it more colour than just a very clean-cut superhero, right? And he's not sort of just out there to just defeat bad guys strictly for that."