Dwayne "The Rock" Johnson will play the iconic Hercules in the upcoming big-screen movie Hercules based off the graphic novel Hercules: The Thracian Wars, and ET's Brooke Anderson recently sat down with the action star, 41, to talk about his stunning
transformation to play "the world's first-ever superhero.
"I have never worked so hard for a role before," Johnson says. "And I appreciate the work, and in this case, I prepped and trained for eight months. It was a very, very long prep, and an insane diet that was very, very detailed. But the thought behind it is, you get one shot to play Hercules ... so I was going to bust my butt."
Pics: Must-See Movie Stills -- Dwayne Johnson as 'Hercules'
And the preparation far exceeded just physical training: Johnson also reveals that they had Oscar-winning wig and even beard designers on-set and, of course, he had to fight in a leather loincloth!
"That was fun, the leather loincloth," Johnson laughs. "At the end, you're having this big, epic battle and a lot of times, sometimes, you fall down, the legs go up in the air and things happen and things get seen, and a whole bunch of interesting magic goes on over there ... and you're like, 'Wow, there's Hercules -- more of Hercules you don't need to see.'"
Video: Dwayne Johnson's Emotional Moment
Hercules hits theaters July 25, and tune in to tonight's ET to catch a sneak peak at the first scenes from the trailer, which will debut on Johnson's Twitter Tuesday!