Meet the Extreme Stuntmen Behind Hollywood's Most Epic Fight Scenes

— -- What do the ferocious Spartan battle scenes in “300,” the heart-pounding action in “The Bourne Legacy” and the impeccably choreographed fight sequences in the just-released "John Wick" have in common?

That would be Chad Stahelski and David Leitch -– two of Hollywood’s premiere fight choreographers and stunt coordinators.

Their work appears in virtually all of the great action movies in recent memory -– “Hunger Games,” “The Matrix,” “Mr. and Mrs. Smith,” “Troy,” and many more.

Veteran Stuntmen Become Directors With 'John Wick'

Stahelski and Leitch invited “Nightline” to 87Eleven Action Design -- their one-stop-shop gym, stunt training and production studio in Los Angeles -– to demonstrate how the biggest action stars learn how to kick butt on-screen.

“Keanu has been here,” Leitch said. “Ryan Reynolds, Scarlett Johansson Chris ... Hensworth, Chris Evans, the cast of 'The Avengers' ... Hugh Jackman ... Stallone, Schwarzenegger’s popped in.”

87Eleven also employs a roster of Hollywood’s best stunt doubles. Sam Hargave doubled as Chris Evans in “Captain America.”

“I work with a lot of actors who are physically talented but [Evans’] memory his recall for choreography and for physical movement is incredible,” Hargave said. “He can jump higher than much more athletic than me as far as natural ability if he had put his energy into doing stunts I’d be out of a job.”

Heidi Moneymaker trained and doubled Scarlett Johansson for her role as Black Widow in “Ironman 2” and “The Avengers.”

“We work really well together. She’s a hard worker,” Moneymaker said. “She likes being involved. She likes to try the stunt, she likes to try it. There’s a wire or something and she likes to be involved.”

And her sister, Renae Moneymaker, doubles for Jennifer Lawrence as Katniss in the “Hunger Games” series and Mystique in the “X-Men” series.

But what makes Stahelski and Leitch stand apart from other stunt double powerhouses in the business is their unique approach to landing the biggest action jobs. When they hear about a major project, they essentially storyboard and direct a stunt sequence -- choreographing, shooting and editing a full scene to present to directors.

“We were like we want the job, we want to do this movie here’s what you could have,” Stahelski said. “It was like mini-film school.”

Both Stahleski and Leitch got their starts as stunt doubles for Hollywood action greats – Stahelski doubled for Keanu Reeves in “The Matrix” trilogy and Leitch doubled for Brad Pitt in “Mr. and Mrs. Smith” and “Troy.”

But they upped the ante for "John Wick," pitching themselves to the studio as potential directors -- not just stunt coordinators or second unit directors -- for the project.

“They know how to make a movie," Keanu Reeves told "Nightline." "When I sent them ‘John Wick,’ I was hoping ... that they could bring something unique to it because of their experience, but I was secretly hoping that they would direct it."

One thing is clear, as long as Hollywood is doing epic fight scenes, it’s a good bet Stahelski and Leitch will be behind them.