The director told Entertainment Weekly that he has shot parts of the next two instalments in the Avatar franchise to avoid having the younger actors age out of their roles.
While performance-capture VFX can transform the actors into their blue alien-like characters, it cannot do much to prevent growth spurts.
Cameron wanted the films to remain as authentic as possible and referred to the Stranger Things casting as something he was aiming to avoid.
“I love Stranger Things, but you get the Stranger Things effect where they’re supposed to still be in high school, and they look like they’re 27,” Cameron said.
Trinity Jo-Li Bliss, who plays Tuk, was seven when she was cast in the role. Now, she is 13. Similarly, Spider actor, Jack Champion, was cast at age 12, and is currently 18.
Champion, in particular, was “growing like a weed” during filming.
“We shot with Jack when he was 14 and 15, almost up to 16,” Cameron explained. “So we were shooting him over an 18-month period.”
Avatar 3 and the start of Avatar 4 take place very close together. However, there will be “a big time jump” towards the second half of the fourth movie.
Speaking of the actors, Cameron said: “They’re young men, young women at that point when we get to the B side of that time jump.”
“I enjoy seeing them grow up as people, and I’m very proud of the young – I’ll even call them adults – that they’ve all become,” franchise producer Jon Landau said. “I think audiences will want to go on the journey with them.”
Landau also confirmed that fans can assume “that the majority of the cast is returning for the third film and the subsequent films”.
She spent her time with them having lessons in underwater sign language, parkour, free diving, breath holding, and knife fighting.
Weaver said: “I was determined to keep up with these kids, who have endless energy and flexibility. I’m really happy about that because we do have to be our own little mob. By that time, I felt like one of the little rag-tag kids.”