Corey Feldman has no idea what it’s like not to be famous. After all, he starred in a McDonald’s ad when he was just 3 years old.”I literally was famous before I knew my own name,” he said in an interview with ABC News’ “Nightline.”The ad led to roles in films such as “Stand By Me,” “Goonies” and “License to Drive.” He was a household name before he could read.”I knew … to respond to Corey, but I didn’t know how to write it; I didn’t know how to spell it,” he said.But being famous and underage, he said, caused serious damage to him and his friends, including loss of innocence and a lost childhood.Watch the full story on the “Primetime Nightline: Celebrity Secrets” special “Underage and Famous,” airing TONIGHT at 10/9c on ABCFeldman blamed the adults around him, not just those looking to profit from charming children, but also some with far more sinister motives.”I can tell you that the No. 1 problem in Hollywood was and is and always will be pedophilia. That’s the biggest problem for children in this industry. … It’s the big secret,” Feldman said.The “casting couch,” which is the old Hollywood reference to actors being expected to offer sex for roles, applied to children, Feldman said. “Oh, yeah. Not in the same way. It’s all done under the radar,” he said.”I was surrounded by [pedophiles] when I was 14 years old. … Didn’t even know it. It wasn’t until I was old enough to realize what they were and what they wanted … till I went, Oh, my God. They were everywhere,” Feldman, 40, said.