The 'Green Lantern' star brings the character of Guy to life in the caveman comedy.
The 36-year-old actor expected to breeze through his first animated project as he would only have to work for a few hours a day instead of the long days he's used to on set, reported Us magazine.
"The producers booked me for a few three-hour sessions. I was like, 'Are you kidding me?'"
"My voice was gone. I was tapped out," he added.