Film producer Joel Silver offered Robert Downey Jr a role in thriller GOTHIKA to test whether the actor had truly put his troubled past behind him.

Silver, who produced The Matrix in 1999, was persuaded to consider Downey Jr for the movie by actor Mel Gibson, who promised the shamed star had cleaned up his well-publicised drug problem and was ready for serious acting.

And Silver was so blown away by his performance, he immediately snapped him up to star as HARRY in new film Kiss Kiss, BANG BANG.

He says, "He (Gibson) was very anxious to help, so he called me up and said, 'If anyone's going to help him, now is the time - he's cleaned up and he's ready to work. He has insurance issues but he really is in great shape.'

"So I put him in Gothika, we took care of the insurance issues, gave him a small salary and he got through it perfectly.

"I saw that this guy is phenomenal - he was great for the role of Harry."