WTF! ROBERT DOWNEY JR. TALKS ABOUT COKE BINGES WITH HIS DAD!

Robert Downey Jr. is an "Iron Man" indeed: The bad boy actor admits he felt the safest he's ever been when behind bars.
"When the door clicks shut, then you are safe," says the veteran actor, who spent a good amount of time between 1996 and 2001 in prison for drug use and possession. "There is nothing aside from a rogue correctional officer that can do you harm if you have the right cellie. You are actually in the safest place on Earth. Safe from the intruders."

For Downey, those intruders were his addictions — which started when his father, Robert Downey Sr., reportedly began giving him drugs when he was just 8 years old, and didn't stop.

In the upcoming issue of Rolling Stone, Downey talks about everything from doing cocaine with his pops and — drumroll, please — Jack Nicholson, to his eventual downward spiral into a heroin addiction.

Recalling one particularly bad trip after his first time behind bars, the actor says: "It was the only coke that ever tasted as good as the coke I did with my dad and Jack." The bender led to a heroin spree with the son of a "local phenom."

"All those years of snorting coke, and then I accidentally get involved in heroin after smoking crack for the first time. It finally tied my shoelaces together."

Downey admits that when he was low, he was really low.

"Smoking dope and smoking coke, you are rendered defenseless. The only way out of that hopeless state is intervention," he tells the mag, on stands Friday.

Downey finally got that intervention in 2003, when he entered rehab (and got "the best shrink in America") and successfully turned his life around.

Now sober for seven years, Downey plans to stay that way. "The ramifications of a little slip are not what they used to be," he says. "It's not kid stuff anymore."

Now the actor is looking forward to the future — namely "Iron Man 2" and growing old with his wife, Susan Downey.

"Now I think, 'Oh, my God, me and the missus will be [in our L.A. home] until the grandkids attend our funerals.' We'll always be here. We'll never f—ing move from here. Crazy."