The former "Game of Thrones" star portrays the titular DC Comics superhero in the new movie, in which he reprises his role as the King of Atlantis from 2017's "Justice League", and his daughter Lola, 11, and son Nakoa-Wolf, 10, snagged brief appearances in crowd scenes during a shoot on the Italian island of Sicily.
Earlier this year, Jason claimed their cameos had failed to make the finished film: "They were in it but James Wan cut them out... They were these beautiful little kids in a Sicilian village and he cut them out," he told E! News back in April, revealing his kids were "so sad" at the news.
Jason encouraged them to take up the matter with the director himself, and when Lola confronted James about the confusion, he insisted their movie debuts were safe.
"My daughter rolled up (to James) like, 'You cut us out of the movie?' " Momoa recalls to Entertainment Weekly, to which James replied, "No, no, no, no, no, you're back in the movie!"
Although Jason was happy to have Lola and Nakoa-Wolf, his children with his actress wife Lisa Bonet, shoot the short scene, he has banned them from following their parents and half-sister Zoe Kravitz into Hollywood.
"They were really excited to be in it," he says. "I was like, 'Don't be so excited to be in a movie... you're not allowed to act.' "
Jason embarked on the global press tour for "Aquaman" in late November, but he has yet to see the completed movie because he is waiting to attend a U.S. premiere with his family.
"It's not that I don't want to (see the film), it's just that my babies were with me when we shot it, and they're 10 and 11 and I can't think of anything cooler than just being with them and all feeling it together (for the first time)," he explains on breakfast show "Good Morning America". "They can't really watch a lot of things I'm in, so it's a first!"