It’s quite endearing, as is his story of how he ran down a mountaintop when he got the casting call.

Dune Jason Momoa

With Denis Villeneuve’s film adaptation of Frank Herbert’s novel Dune now playing to largely wide acclaim, diehard fans of the book can expect several nods and references to the source material that casual fans may miss. But there’s one Easter egg that actor Jason Momoa included that was made for an audience of one — and has nothing to do with Herbert’s novel.

Speaking with IndieWire, the Aquaman and Game of Thrones star revealed a subtle message he slipped into the film for his son. Momoa, who plays Duncan Idaho, House of Atreides swordmaster and mentor to Dune’s hero Atreides (played by Timothée Chalamet), said that they “did a bunch of stuff like Kali” in the film, which is the national martial art of the Philippines. Although this martial arts style was something he had “never really learned” prior to filming, he knew his son was very familiar.

“My son does that,” Momoa said. “There’s definitely these intimate moments where I’m signaling to my son. That’s a Kali move, where you put your hand on your heart and put it on your head. That’s to Timothée in the movie, but that’s to my son in real life.”

That’s… incredibly endearing. Also endearing? The story Momoa tells about running down a mountain while at Sundance 2019 when he got the call to play Duncan without auditioning.

“I got a call from my agent literally on top of a mountain, and I was shocked, and he was like, ‘Denis Villeneuve wants to talk to you right now,” said Momoa. “I thought it was a prank. He said, ‘He wants to talk to you right now. He wants you for a role. He won’t tell anyone what it is.’ Me and my best friend, who loves Denis, ran down the mountain, into the room, FaceTimed him, and he had everything laid out.”

Momoa went on to add that Villeneuve “had this whole department there in costume. Everyone was staring at me, and he had a whole book. It was this manifest. Pictures, everything. It was almost like he was pitching it to me, and I was taken aback. He asked if I would play Duncan. That’s never happened before.”

Since Villeneuve’s film only covers roughly half of Herbert’s novel (hey, it may be a fun read, but it’s also a dense one), fans are wondering if Warner Bros. will give the thumb’s up to a second film. But if and when that happens, Momoa is already on board.

“I finally saw Denis at a cocktail party, and I was picking his brain going, like, ‘Hey, what’s up buddy? What are we doing? I’m ready,’” said Momoa. “We’ll find out.”

Dune is currently playing in theaters and streaming on HBO Max.