Filming the sequel to “Avatar” wasn’t easy on the actors.

In an interview with Vanity Fair, director James Cameron revealed that actor Jack Champion, who plays the human character Spider in “Avatar: The Way of Water” had to shoot his scenes twice.

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“The beauty was, we got to do it twice,” he said. “So [cinematographer] Russ [Carpenter] would light the scene, so everything that we did with Jack photographically, we did previously with him in terms of capture.”

Shooting twice was necessary so Champion could be a reference for his co-stars’ motion-capture performances as the film’s Na’vi characters, before doing his live-action takes.

“Jack did his entire performance twice, once for all the other actors like Sigourney and Britain [Dalton] and Sam, so that he was there kind of off camera,” Cameron said. “And he was like 13 at the time. And then later when we shot, he was 15, so he changed in size and vocal range a bit, but we capped him and then we had these capture scenes.”

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Champion wasn’t the only actor who went through real challenges during the shoot.

Many of the actors learned to hold their breath for minutes at a time for the film’s underwater sequences, including Kate Winslet, who held her breath for over 6 minutes.