CHAPLIN star Robert Downey Jr's efforts to quit smoking have failed - much to the horror of his 12-year-old son INDIO.

The reformed drug addict had promised his son that, after marrying producer Susan Levin in August (05), he would focus on ditching his nicotine habit.

But he admits that it's proved a lot tougher than he envisaged - even after receiving hypnotherapy.

He says, "I went to the hypnotist and he screamed at my subconscious and then I was fine. He was like, 'Do you wanna die from it?' I was like, 'I'm supposed to be relaxed!'

" It's not his fault. I'm smoking again and I feel ghastly about it.

"(My son) is not helping me quit, he's hiding my damn cigarettes. That's like keeping Dr Jekyll's potion away from him for two hours. He's just gonna go back to the lab and make another batch."