Forget swimming and all the stunts -- Jason Momoa had other major challenges playing the title character in "Aquaman."
"It looks like it's easy to pee in that, but really it's not," he told EW. "And if you have the poopsies, it is very challenging. You've gotta be really good at holding it."
Some fans had agonized over the superhero suit, hopeful that Momoa would don the traditional look, complete with a trident.
Those concerns became just water under the bridge after the film's director, James Wan, tweeted a photo of the movie poster in October showing a part of the costume.
"A Son of the Land... A King of the Seas... He's the Protector of the Deep," Wan tweeted. "Something arrives tomorrow."
That "something" turned out to be an extended trailer which featured Momoa in full classic costume as Arthur Curry/Aquaman.
Amber Heard stars as Mera in the film, and talked to EW of being "vacuum-sealed" in her costume.
She said that hers and Momoa's outfits in the movie are "a whole other level of functional art."
"They're so intricate," she said. "You have to move in it, you have to breathe in it, you have to live in it."
"Aquaman" opens in theaters December 21.