For Cameron, life is a constant juggling act between his two passions - filmmaking and deep-sea exploration.
While many remember Cameron directed Titanic, they perhaps don't know the Oscar-winner also travelled to the ship's grave site himself and directed the 3D IMAX documentary Ghosts of the Abyss in 2003.
Although he's known for sci-fi flicks, including Aliens and The Terminator, in another underwater doco Aliens of the Deep, he got up-close to the strange beings living far beneath the surface of our own planet.
And when Avatar was in production, it wasn't the only record-breaker being made.
At the same time Cameron was making the world's highest-grossing movie, a submersible was being created so he could dive to the deepest possible part of the ocean.
It was a feat he achieved on March 26, 2012, and the claustrophobic expedition is now the focus of a new documentary Deepsea Challenge 3D.
But with that done and dusted (bar the press tour), Cameron says, "now I'm fully dedicated to Avatar 2, 3 and 4".
"Which are sort of, I call a mega project because we're doing all three together," he told AAP in Sydney.
"Where I am right now is the scripts are almost done, much of the preliminary design work has been done, so new creatures design, new settings, environments, other places you'll see on Pandora and other places in the Avatar universe.
"So it's all coming together, it's all right on track."
He says it's not typical, but they're making all three at once and then they will hit cinemas one after the other over a few years.
"They'll drop a year apart, so they stay within the public consciousness as one big story," he says.
"Christmas 2016, Christmas 2017 and Christmas 2018 is the target."
The countdown is on.
