Dwayne Johnson's fear fueled an MMA-style transformation for his most challenging role yet

Dwayne "The Rock" Johnson put his fears aside to take on a very different role than the action-packed parts he's known for.

Johnson transformed into MMA fighter Mark Kerr for the sports drama, "The Smashing Machine." In an interview with Vanity Fair, Johnson explained that this was the first role in years that made him nervous.

"It was very real. I had not experienced that in a very, very, very long time, where I was really scared and thinking, I don't know if I can do this. Can I do this? 

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"I realized that maybe these opportunities weren't coming my way because I was too scared to explore this stuff," he told the outlet. 

To properly take on the role, Johnson had to be plastered with 13 to 14 prosthetics every day and would just "disappear" when he walked on set.

"I just sat in front of that mirror for three to four hours and watched it all change. There were about 13 or 14 different prosthetics. Subtle, yet I think very impactful. By the time I got to set, I was Mark Kerr and I felt it, from how he walked to how he talked and how he looked at life," he said.

Johnson became familiar with Kerr's story after seeing it portrayed in the 2002 documentary, "The Smashing Machine." In the doc, he saw Kerr battle his painkiller addiction, which hit close to home for the actor.

"I lost a lot of my friends to addiction and to suicide - in the late '90s, early-to-mid 2000s, there were a lot of untimely, very early deaths," Johnson recalled.

"What a walking contradiction in the most beautiful way Mark was and still is. Soft-spoken, sweet, kind-yet at one time the most lethal man on the planet," Johnson said.

After watching the documentary, he immediately respected Kerr for getting himself out of a dark situation and hoped to play him on screen one day. 

Fast-forward two decades; Johnson was given the opportunity by Benny and Josh Safdie. Johnson's "Jungle Cruise" co-star, Emily Blunt, also stars in the movie as Kerr's then-girlfriend, Dawn Staples.

Dawn and Mark's volatile relationship will be a focus of the film. The couple's final fight takes place at their home and Safdie made sure to hide the cameras in the movie set. 

"You didn't see a camera - you didn't see a light, a setup, nothing," Johnson told the outlet.

Blunt chimed in, "It was like 'High Noon' in the kitchen a lot of the time, and that was incredibly transporting and rattling, because you don't have the technicalities around you that help you flash in and out of this pain of what you are portraying. 

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"We would be shaken. The movie was sponsored by tequila, just for us to come down from some of those scenes. They were bonkers to try to come back to earth from."

Blunt was able to look at Dawn and Mark's relationship from another perspective, since she was able to work closely with the pair during filming.

"However eruptive that relationship was, it was centered in this huge need for each other - a codependency," Blunt said. "It's an all-consuming existence to be a fighter, and you need everybody in your life to get in line with that. I just don't think Dawn was the kind of person just to get in line."

She continued, "I've actually never played somebody who is still with us. I'm very grateful to her…. I just needed to be her advocate."

Johnson credited his close friendship with Blunt for their on-screen chemistry.

"If Emily and I weren't best friends, I don't know that we could've gone to the places we went to. That closeness created the trust, which then allowed for the vulnerability, which then allowed for [us to] go anywhere," he said.

Blunt echoed similar remarks about her co-star and told Vanity Fair, "It seemed to be an effortless immersion - like a full disappearance, spooky. From day one, he was elsewhere." 

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She added: "He has absorbed and borne witness to so much of what Mark has experienced that it was such a beautiful thing to watch this person let go of having to be an image, of having to be The Rock, and crack himself in half for this role."

Johnson is grateful to be taking on a different role than those he's used to, such as "Jumanji" and "Red One."

"After all these years I've been making movies, it became so glaring to me. It's almost like a… There's a song from George Strait called 'Where Have I Been All My Life?' This reminded me of that. Where have I been? 

"The thing I was fearing is the thing that actually gives me the greatest peace - a safe place to explore all this stuff that I've experienced over the years. I have a place to put it," he said.

"The Smashing Machine" premiered Labor Day Weekend at the Venice Film Festival and will be released in theaters Oct. 3. 

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