When Titanic director James Cameron released his film Avatar last year, there were not as many theaters equipped with 3D equipment to screen the 3D version as he would have liked.

So, on Friday, film studio 20th Century Fox is releasing an Avatar: Special Edition version of the biggest blockbuster of all time ($2.7 billion in global ticket sales) exclusively in Imax 3D theaters and venues equipped with digital 3D.

Cameron spoke to Reuters about the nine minutes of new film on the special edition, the movie's success, and whether movies or science is his favored pursuit.

Q: Why a new one? The first was pretty good.

A: There are a couple of factors. There's footage I think people would be interested in. I don't want to completely reinvent the movie and turn it into something it's not. It's really more an embellishment; it's a fuller experience.

The other factor is I think people want to see 'Avatar' in movie theaters. That's just my instinct. This all came about because when Alice in Wonderland came out, they had booked all the Imax 3D screens. We were still doing well, still selling out ... but we lost all those screens in one night. So, we knew there was still a market for people seeing the film.

Q: Many people, me included, thought, 'they already made $2.7 billion! How much more do they want?' Money grubbers?'

A: Yeah, we are just money grubbing vampires. (smiles) No, I think making money is called good business. At least, in this country it still is. And two, it's a side-effect of giving people what they want. If we're correct and this is what people want, then we've done a humanitarian service (laughs).

Q: Right, Hollywood does perform humanitarian services.

A: Sometimes. (laughs again) Sometimes it can, but it's usually just liberal guilt...

No, it's like an illuminated manuscript, there's just more to it. I also want to encourage people to remember the movie in 3D on the big screen. And this will be the last hurrah ... It'll disappear from big screens -- other than an occasional Imax may want to book it -- for 10 years, 20 years, maybe forever.

Q: So, the new footage, what are people going to see?

A: We got different kinds of stuff. Some of it little things, 10-, 15-, 30-second pops that just show up here and there where if you've seen the movie, you'll ask yourself, 'did I see that before, or is that new.'

Then, there are going to be things like a big action scene where they hunt these herd animals that didn't even exist in the first movie because we'd cut them out. There are new creatures, a big flight scene, almost like a Buffalo hunt. I think it's one of the top visual scenes in the film.

There's an emotional scene that plays out at the end where Tsu'tey is dying and there's a very emotional scene with Jake and Neytiri. Everybody thought I was crazy when I took it out. I did it for pace and tempo, but I was playing it pretty conservative. I was concerned about eye fatigue on a 2-hour and 40-minute film. I was concerned about sensory overload...

We never got much criticism about length. I was expecting a lot. I was expecting at least critics to say, 'really good film' or 'pretty good film, but too long,' but we didn't get much of that. It seemed like we had permission to go longer.

Q: So, you and Fox have the two top grossing films of all time. Can you now get about anything you want from Fox?

A: Do they listen to me more, now? Probably not, if they weren't going to listen to me after 'Titanic,' they're not going to listen to me now, any more or any less.

Q: You're doing another 'Avatar' film. Is there a third?

A: The next script will be essentially two scripts, and I don't know if we'll shoot it together or shoot it separately. We'll release it separately, obviously.

If that works, there will probably be another one, but at that point, I probably won't be directing them. I do want to do the second and probably the third film myself just because it's so much a part of me and my philosophy and ideas.

Q: Beyond movies, you've become a bona fide expert on deep underwater exploration. When all is said and done, what do you want to be remembered for -- big movies or exploration?

A: What goes on the tombstone? (laughs)

Q: Well, without having to ask it that way, yes.

A: I'm satisfied with 'innovator' because it requires innovation to do all this deep ocean exploration. We're building lights, cameras, robotics, submersibles, fiber optic systems, and I love all that stuff. I love imagining something, building it, and making it work in the ocean...

On the filmmaking side, there's the innovation of how you make the movie and there's the innovation of what the movie is, meaning the story, the characters, the creation of a world, the imagination required for that. I love all that stuff. The problem for me is task managing in such a way that I don't get so focused on one that I forget about doing the other.