Stephen Lang says that the long-awaited Avatar 2 will be similar to the first movie, but with an underwater setting and "on steroids." The 2009 box office was dominated by the release of James Cameron's visually groundbreaking story of humans interacting with the Na'vi, the indigenous species of the moon Pandora. Avatar was nothing short of a box office juggernaut, breaking numerous records along the way to becoming the highest grossing movie of all time. Although the technical aspects of creating Avatar's visuals were widely praised, some criticism was reserved for the movie's narrative and environmental message.

Given Avatar's financial success, talk of a sequel was immediate, however almost a decade later Avatar 2 has yet to see the light of day. Eventually, it was announced that a grand total of four Avatar sequels had been green-lit and filming finally began in September last year, with Cameron confirmed to be directing and co-writing each installment. Many of the core Avatar cast have also been confirmed as reprising their roles and, interestingly, this includes characters previously thought deceased, such as Stephan Lang's villainous Miles Quaritch.

Related: Dileep Rao Officially Returning For Avatar Sequels

Speaking with Screen Rant while on promotional duty for Braven, Lang revealed in our interview some of his thoughts on Avatar 2 thus far. Lang claims that the sequel won't stray too far from the original but will be largely set underwater and feel "on steroids" compared to the first movie:

Screen Rant: So, just switching gears for a second, in what ways do you see that sequel [Avatar 2] pushing the boundaries like the first one did? Because that movie is groundbreaking, so many movies couldn’t have been made without that movie having been made first. So, it what ways is James Cameron pushing that new technology and new style of film making for the next few chapters?

Stephen Lang: Well, in ways that are probably too numerous or too, kind of, complex or too subtle for me to even articulate right now. I mean, look it’s no secret that we’re doing a lot of underwater motion capture, which, in itself is groundbreaking, it just hasn’t been done.

SR: Yeah, I don’t think I’ve ever heard of that. I don’t think I’ve ever heard of anybody doing underwater Motion Capture.

Lang: No, it hasn’t been done, and it presents a whole host of challenges. But, you know from Jim’s resume you can ascertain that he does enjoy the water.

SR: Yes.

Lang: There’s something about the world being undersea. That is extremely beautiful, fascinating, challenging to him. So, you know, there’s sections that taker place. . . so, that in itself is a big deal. But just, what are we, three months into shooting now, it’s like nothing I’ve done before.

SR: Interesting. . . Are you guys shooting . . .

Lang: It’s in many ways reminiscent of Avatar, but it’s kind of Avatar on steroids.

As Lang himself implies, James Cameron is no stranger to shooting sequences involving plenty of water and this should ensure that Avatar 2's underwater sequences are as beautiful as they are technically groundbreaking. It's also encouraging to hear that the franchise is continuing to push the envelope in terms of filmmaking. After the first movie's huge success, Cameron could have easily pumped out a less strenuous carbon copy, and therefore his desire to attempt something new in cinema is a brave and commendable step. Quite how well the blue Na'vi will show up deep underwater is just one of the many challenges the director faces.

However, fans of the original Avatar will also be reassured by Lang's comments, as it appears that the sequel will not stray too far from the roots of the original. Those concerned that Avatar 2 might have been a complete departure from the dry-land adventures of Jake Sully and Neytiri apparently need not worry. Of course, all sequels must escalate and improve upon their predecessors and not just in terms of groundbreaking filming techniques - so Lang's assertion that Avatar 2 will be like the original but "on steroids" is a positive sign too.

More: How Disney Buying Fox Could Affect The Avatar Sequels