Back in August 1974, daredevil Philippe Petit calmly stepped out on a wire connecting the two roofs of the Twin Towers of the World Trade Center. From more than 1,300 feet up, the 24-year-old proceeded to cover the span of 200 feet — not once, but eight times. It's was and remains an astounding feat of athleticism. So naturally, when it came time for actor Joseph Gordon-Levitt to portray Petit in director Robert Zemeckis' new thriller "The Walk," there was only one person he could turn to pull off the character.

“He’s such an optimist, Philippe," Gordon-Levitt told EW about his eight-day intense training session with the 66-year-old daredevil. "He’s such a positive thinker, and when someone believes that you can do something, then you yourself believe you can do it, and that’s when you can actually do it, when you believe in yourself."

Petit led Gordon-Levitt through multiple training sessions in blocks of 10 minutes each on everything from juggling to engaging his core muscles while walking to maintain a tight stance.

"It became easy for me," the 34-year-old actor told the LA Times. "I could walk forward and backward on a wire that was 2 feet off the ground. No problem. But when the wire was moved up to 12 feet, no matter how much I told myself this is all fine, my body just seized up. As soon as you start thinking that you're really high up, you start shaking. And then, you're sunk."

Beyond the high wire, Gordon-Levitt also employed a personal trainer to increase his upper-body strength and balance. In the end, he could even ride a unicycle.

“I had Joe doing handstands and walking across the room on his hands,” trainer Arin Babaian shared with the Daily News. “We did balance work on a board, lots of core work and pull-ups for strength.”

"The Walk" is currently riding high on with an 83 percent approval rating. Writes critic Brian Truitt for USAToday: "For those who want to feel like they're 110 stories up and living in the clouds, Hollywood does its job conjuring movie magic with a breathtaking Walk to remember."