The actor has struggled with addictions to cocaine, heroin and methamphetamines in the past two decades and he admits his lowest point came when his Heat co-star tried to talk sense to him.
Sizemore, who details the emotional family-led intervention in his new book, By Some Miracle I Made if Out of There, tells news show Access Hollywood, "I walked in to see my shrink and I walked in and there were all these people there... and I sit down and Bob came in and goes, 'Ok. Ok, now we can talk... Now you listen to me, I'm no psychiatrist... but you're either going to go to rehab or go to prison and in walks a cop.'
"I was trying to make a joke out of it because all these people are there and I'm embarrassed and he went, 'Tom, I'm not playing. They'll put you in jail for a year!'"
De Niro then offered to fly Sizemore to rehab onboard his private plane, but the troubled actor insisted he'd check-in as soon as they wrapped their 1995 film.
He recalls, "I did the last scene of Heat and I was supposed to go to rehab right then, but I had my assistant drive my car... and I dove into the backseat of a moving vehicle with my prosthetics on and I drove to the Loews Hotel and I checked in under the name Amiel Gooch, and Bob (De Niro) finally tracked me down over there, and when I knew he was closing in on me, I hung off the balcony."