For a time Robert Downey Jr's professional accomplishments were overshadowed by drug addiction and personal problems that spawned acres of newspaper headlines. But his talent has never been in doubt, from early performances in Less Than Zero and True Believer, through to his Oscar nominated portrayal of Chaplin. Recently married to film producer Susan Levin, he returns to form wonderfully in Shane Black's comedy-thriller Kiss Kiss, Bang Bang, in which he plays a thief who is mistaken for a potential movie star.

So did you like Kiss Kiss, Bang Bang when you saw the finished film?

I loved it, it's such fun. I like that people are seeing it and then talking about it. Like when I took my son and his friends to see Napoleon Dynamite last year, we spent the next six weeks trying to explain it.

Did you feel a great affinity with your character here, Harry Lockhart?

I think he's a combination of both me and Shane Black. But I was a New York kid who came out to LA pretending to be an actor, and - unlike Harry - was eventually taken seriously. I was a little naïve and became disillusioned with it. I was kind of chasing my tail, trying to do the right thing, and was a little irresponsible. But I was grateful for what I had.

Do you think you're better equipped for this role now, after all you've been through in the last few years?

I think you end up doing the stuff you were supposed to do at the time you were supposed to do it.

What was it like working with Val Kilmer as your on-screen mentor, private detective Gay Perry?

Well the first scene we did, where he says: "Colin Farrell wants too much money, you're never going to get this part," is one of the great scenes. It looks cool, and it looks like I'm beginning to be macho. But Harry's so stupid. Perry says "Merry Christmas, sorry I ****** you over." The only retort I have is "Don't quit your gay job!"

Shane Black wrote as well as directed the script. Did this mean he was particularly strict on you sticking to his screenplay?

No, he was great. There was this one scene where Harry bumps into this girl - Flicka - in the airport and I run up to her and compliment her on her ears and her suit. That was because Shane asked me to think of a couple of things that I liked about her that were kind of offbeat.

Having turned your life and career round do you have any wishes for the next few years?

It's not really up to me any more, I just kind of put one foot in front of the other.

Kiss Kiss, Bang Bang is released in UK cinemas on Friday 11th November 2005.