“Avatar takes place in another world and you’ll feel like you’ve been to that world. When you see a scene in 3D, that sense of reality is supercharged.

But I made it my mission to keep the 3D out of the actors’ consciousnesses completely. Most of them forgot we were shooting 3D. Then every once in a while one of them would watch some dailies and come back wide-eyed.

We’re making a $200m-plus movie and it’s all about the journey of one guy, Jake. Sam Worthington’s in every scene in the film, from beginning to end. It all hangs on that one piece of casting. And Sam is able to create a character that allows you to walk in his shoes. He’s a star.

There’s a couple of battle scenes towards the end, the last of which is the mother of all battles. It’s the biggest thing I’ve ever done, absolutely.

It’s got everything. Everything. It’s aerial, it’s ground, it’s cavalry, it’s infantry, it’s mech, it’s hand-to-hand, it’s gonzo.”

Avatar is released December 18th