Shia is preparing for the box office debut of Transformers: Revenge of the Fallen — opening in theaters June 23 — and he’s making sure he and his new flick get a lot of publicity.

In an — eh –”candid” interview with Parade Magazine, Shia LaBeouf, 23, credits his sense of humor to “seeing my parents have sex, smoke weed, my mom being naked … [and] twisted R-rated humor.”

“The good actors are all screwed up. They’re all in pain. It’s a profession of bottom-feeders and heartbroken people,” says the actor, who Parade writer Dotson Rader describes as “foul-mouthed, resentful, funny, prickly, quick-witted, and charming — a package of contradictions.”

Shia also opened up about his breakup with China Brezner, who he dated for three years.

“Maybe it was career pressure,” Shia says of the split. “Maybe I chose work. Every man has those feelings of escape and survival. I know you shouldn’t be that way. I’m trying to understand it and find the answers. I don’t have them now.”

He continued, “Why did the love of my life and I break up? … Man, I have no idea. What was that all about? I have no answers to anything. None. Why am I an alcoholic? I haven’t a damn clue! What is life about? I don’t know.”

Check out Shia’s full interview with Parade Magazine when the issue arrives in your Sunday paper inserts June 14.