avatar 01Sam Worthington, of Terminator: Salvation fame, is the lead in James Cameron's long-awaited AvatarThe trailer for James Cameron's Avatar, the movie he's spent the last decade working on, has finally arrived. And from what we can tell, it contains some of the most exhilarating battle scenes we've seen in years.

Watch the Avatar trailer here

It' was international Avatar day last Friday which means a small selection of cinemas and Imax theatres got to show-off fifteen minutes of footage from James Cameron's ten-years-in-the-making sci-fi thriller.

We took a trip over to the London Imax theatre in Waterloo to get a sneak peek at the movie, which was presented by a 60-foot, 3D James Cameron himself.

The clips included a scene in which a paraplegic Marine called Jake (Sam Worthington) arrives at a military outpost on a faraway planet. He hears an introductory speech from Col. Quaritch who informs the assembled Marines that life on the planet may be beautiful, but it is very, very deadly.

The next scene depicted Jake's first experience with the avatar of the movie's title. It's a half-living being that Jake's mind is transferred into (think The Matrix but with large blue beings instead of computer generated leather) by scientist Dr. Grace Augustine (Sigourney Weaver).

What followed can only be described as breathtaking. Jake's avatar goes on an adventure through one of the most impressive fantasy worlds ever to appear on film. He is chased by monsters, wrestles small dragons and meets the planet's indigenous humanoid life forms, the Na'vi. Replete with tall, blue love interest, Neytiri (Zoe Saldana).

And rather than feel forced, the 3D is completely immersive. This isn't about pick-axes coming out of the screen at your face - Cameron wants the world he has created to suck you in and overwhelm you. And that's exactly what it does.

The movie isn't out until December 18th, so it's going to be seem a very long time until you can see Avatar's 3D glory - but in the meantime you can see the 2D trailer here in High Definition.