Actor Scott Haze almost drove himself crazy spending three long months sleeping in caves in the chilly mountains of Tennessee in preparation for his role as a violent killer in James Franco's new movie Child Of God. The film, an adaptation of author Cormac McCarthy's 1973 novel of the same name, revolves around Haze's character Lester Ballard, a troubled man who retreats into the caves and descends into madness and murder, killing women and having sex with their bodies. Haze reveals he became a real-life caveman himself, surviving on only one piece of fish and an apple each day, in an effort to fully understand Ballard's mindset - and he only quit the exercise when the weather became too cold for him to continue. He tells the Associated Press, "I knew that this was a role that I had to go to crazy extreme lengths... I slept in caves many nights with bats all around. It was crazy. I let everything go, just hung out with the hillbillies and stayed as isolated as possible." The fish and fruit diet caused his weight to plummet from 195 pounds (88 kilograms) to 150 pounds (68 kilograms) and his dedication to the role surprised Franco, who had no idea his leading man had literally become a caveman until Haze turned up for the first day of filming, looking and acting completely in character. Speaking at a press conference for Child of God at the Venice Film Festival in Italy on Saturday (31Aug13), Franco said, "(Haze) didn't really talk to anyone, stayed to himself, and was like that for the whole shoot." Franco also hailed 25-year-old Haze's acting in the movie as "the performance of a lifetime". Writer McCarthy based the character of Ballard on real-life Wisconsin murderer and body snatcher Ed Gein, the notorious 1950s criminal who also served as the inspiration for Psycho's Norman Bates and Leatherface in the horror hit The Texas Chainsaw Massacre.