Kevin Mazur / VF14 / WireImage 1 / 8
Kevin Mazur / VF14 / WireImage 1 / 8

Edward Norton has portrayed several heroes of the silver screen over the years, but apparently he's one in real life too -- and not just because of his work as an environmentalist!

According to actor and documentary director Fisher Stevens, the erstwhile Bruce "Hulk" Banner once saved pal Leonardo DiCaprio's life.

Fisher recounted the time that Leo almost died while scuba diving in the Galapagos back in 2010 while discussing "Before the Flood," the climate change documentary that he directed and the Oscar winning actor executive produced, with GQ magazine.

The duo were diving with Edward Norton as part of a TED conference expedition with oceanographer Sylvia Earle when things suddenly took a scary turn.

"We go down and we see 300 Eagle Rays and Spotted Rays and it was an amazing dive," said Fisher. "Leo bolts away with Sylvia, and Edward goes in front of me and the next thing I know after twenty minutes I'd lost them all. Then, I see Leo buddy breathing [a rescue technique used when two divers share one air valve], because Leo's tank was leaking oxygen, and Edward had to save him! It was pretty crazy."

Concluded the director, "[It] was good for a second and then it got pretty shaky when he couldn't breathe. But we really bonded on that trip."

The diving mishap is hardly Leo's first brush with death -- it's not even his first diving-related brush with death.

He once came face to face with a great white while diving in South Africa after the shark jumped for some chum and landed halfway in the actor's protective cage.

"My friends have named me the person they least want to do extreme adventures with, because I always seem to be very close to being part of a disaster," the Oscar winner told the January 2016 issue of Wired magazine. "If a cat has nine lives, I think I've used a few."

Speaking of being "very close to being part of a disaster," the star of "The Revenant" is doing his part to avoid doing just that with "Before the Flood," which chronicles how climate change is affecting the environment and what society can do prevent the extinction of endangered species, ecosystems and native communities across the planet.

The film debuts on Oct. 30, 2016.