Sharing the same hobby as Cameron, Landau, the director's longtime collaborator who also produced Titanic and the first Avatar movie, says: "One of the great things about diving is that every time you go diving, you don't know what to expect."

Shifting their passion for ocean into a visual spectacle, Landau recalls that they took the cast to rehearse in the rainforest and the ocean in Hawaii, training them to snorkel and hold breath in the reefs. Most of the actors and actresses had little diving experience before, so they were taught to scuba dive and free dive, helping them to feel comfortable in the water and to easily imagine the oceanic environment on Pandora.

"We did what could be perhaps the most Pandora-like thing you could do on Earth. We went on a night dive. We went down 30 feet (9.1 meters) and sat in the dark at the bottom," says Landau, adding that the stars were amazed to see a school of manta rays swimming toward them from the darkness.

Recounting the moment that the cast got to interact with these highly intelligent creatures, Cameron notes that Cliff Curtis, the New Zealand actor who plays the leader of the Metkayina race, has a manta ray tattoo on his chest, which, for him, holds a deep meaning.

"And then all of a sudden, he (Curtis) was having this almost spiritual relationship by touching these amazing creatures, as they were swimming around," says Cameron.

A father of five children, with the youngest turning 16 years old, the director, who is also known in Hollywood for his hot temper, shows his soft and caring side, injecting the personal emotion of being a parent into the tale.

"We put all of our energy into making it a great visual experience, like a journey. But we also put more energy this time into telling the story of family," he explains.