James Cameron punched diver in the face after he almost died while filming underwater

James Cameron has opened up about nearly dying while filming underwater for a movie.

Cameron, known for pushing actors to the brink while filming underwater for Avatar 2, had a dicey encounter below sea level himself while making one his several other ocean-based films.

Catch the trailer for the movie which nearly cost Cameron his life here:

During a Q&A session after a special edition screening of his 1989 sci-fi movie The Abyss at Beyond Fest in Los Angeles, Cameron recalled a moment during filming when his scuba diving equipment malfunctioned, leaving him struggling to breathe.

Cameron was working 30 feet below the surface, wearing 'heavy weights' around his feet and waist so he could 'move the camera around on the bottom'.

Cameron said, as quoted by Variety: "When the tank gets low, you get a warning that you’re about to run out of air. Well, this thing had a piston servo regulator in it, so it was one breath... And then nothing.

"Everybody’s setting lights and nobody’s watching me. I’m trying to get [underwater director of photography] Al Giddings attention on the p.a. but Al had been involved in a diving accident and he blew out both eardrums so he was deaf as a post.

"I’m wasting my last breath of air on an underwater p.a. system going ‘Al… Al…’ and he’s working away with his back to me."

Getty Images/ Frazer Harrison

Cameron explained the 'safety diver' managed to get 'about ten feet from the surface' and stuck a regulator in his mouth.

However, the regulator hadn't been checked and had been 'banging around the bottom of the tank for three weeks and had a rip through the diaphragm'.

"So I purged carefully and took a deep breath… of water. And then I purged it again, and I took another deep breath… of water," Cameron continued. "At that point it was almost check out point and the safety divers are taught to hold you down so you don’t embolize and let your lungs overexpand going up."

But Cameron - an experienced diver - 'knew what [he] was doing'.

He said: "He wouldn’t let me go, and I had no way to tell him the regulator wasn’t working. So I punched him in the face and swam to the surface and therefore survived."

Similarly to Cameron, The Abyss may've sunk a little when it was first released back in 1989 compared to how most of the director's other movies have sailed past box office records.

However, it's bobbing its way back to the surface, set to be available to stream soon, with the director confirming the 4K restoration of the movie has been completed.