Meanwhile, Johnson says he told the director to add "smoldering intensity" to Bravestone's special skills to have more fun, a suggestion which was accepted by Kasdan.

"This role is different from my other tough-guy roles, because he has no weakness," says Johnson.

As for the other roles, Jack Black plays Professor Sheldon "Shelly" Oberon, a chubby middle-aged cartographer, cryptographer, archaeologist and paleontologist who has a pretty and popular teenage girl's avatar, which brings a lot of laughs.

And then there is Karen Gillan, who is known for portraying Nebula in the Marvel Cinematic Universe films Guardians of the Galaxy.

She plays Ruby Roundhouse, a commando, martial artist and dance fighter who is Martha's avatar.

Gillan is no dancer or fighter, so it took her several weeks of practicing dancing and fighting to be ready for the role.

"I'm basically acting as myself in the whole movie, as I was kind of nerdy and tall with red hair at high school," says Gillan.

"I hope I can present girl power in the film because the role is of someone who is not confident and good at social contact at first. But then she gradually finds her inner power through the avatar's body."

The film was shot in Honolulu, Hawaii.

In the movie, Kasdan tries to use real shots as much as possible and all the animal scenes were created using computer-generated technology.

Describing how the filming was done, Kasdan says: "There is one scene where the characters are in a helicopter trying to escape from a bunch of rhinoceros. But actually when we were shooting there were no rhinoceros, and the actors had to perform using their imagination.

"But it took us a whole year to add the rhinoceros through CGI to that scene."