Dwayne "The Rock" Johnson revealed the reason behind his recent slim down that left fans surprised.Johnson, 53, explained that he's been losing weight for an upcoming film called "Lizard Music." He described his character, the Chicken Man, as "a very whimsical and eccentric 70-something-year-old man called the Chicken Man. And his best friend is a 70-something-year-old chicken," and joked that in preparation for the role, he's been eating "less chicken.""I'm so excited because I get a chance to hopefully transform again like I was able to do in ‘Smashing Machine,'" he said at a Toronto International Film Festival event on Sept. 8, per People. "Can't wait.""This is me slimmed down," Johnson said. "In the process of slimming down. I still have a long ways to go."DWAYNE JOHNSON'S FEAR FUELED AN MMA-STYLE TRANSFORMATION FOR HIS MOST CHALLENGING ROLE YETJohnson debuted his leaner look at the Venice Film Festival on Aug. 25. The actor's lean look was captured in video from the event."Yep had to do a double take.." one X user commented."He’s so lean," a fan commented."The Rock slimming down and still owning every room…legendary glow-up unlocked," another chimed in.LIKE WHAT YOU’RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWSBefore slimming down, 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?"He added, "I realized that maybe these opportunities weren’t coming my way because I was too scared to explore this stuff."CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTERTo properly take on the role, Johnson wore 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.Fox News Digital's Janelle Ash contributed to this report.