The 39-year-old 'Charlie's Angels' star, who has starred in countless films, prefers to become the character while portraying them, reported E!Online.
"I don't think I'm a good actress. I feel like it's fake and yucky and it doesn't ring true," Barrymore said.
"But if you research and you study and make it personal, you just become that person, and it's your truth and everything else around you falls away. Then you're telling the truth, it's not lying, it's not fake," she added.
"Steven told me, 'Don't act your characters. Be your characters'. At (the age of) six, I guess I was comfortable and more humorous than I would have remembered now," she said.
"But once I got older and kept continuing acting, I don't know if I would have succeeded without that advice, because that's the thing that saved me. I'm not an actor, I'm a pretender," she added.