Against all expectations, and backed by a certain Hollywood A-lister, he's back clean and sober to star in a new film version of The Singing Detective.

Robert Downey Jr. is looking rather handsome today. He's looking fit, he's looking tanned, he's looking healthy, and he's doing his very best to look relaxed. He greets me with the kind of 100 watt smile and candid eye contact that you might use to mask your feelings on a blind date, and he's dressed, rather startlingly, all in green, including a T-shirt emblazoned with a four-leaf clover and the word 'lucky'. Is he the luckiest man in show business? Arguably - if you measure luck in terms of sheer survival. He's come through drug addiction, jail terms, tabloid crucifixion, public mockery, and a lengthy spell in rehab to reach this point, and he's got a film to promote now because Mel Gibson had the balls to cast him when no insurer - and therefore no producer - would touch him with a barge pole. Downey knows he's going to have to come clean about all this. So he sends out for a coffee, perches attentively on the edge of a sofa, lights a cigarette, and goes to work.

The film we're here to talk about, The Singing Detective, is both painfully apt and somewhat dangerous as a comeback project. This adaptation - by Dennis Potter himself - of the 1986 TV classic ticks lots of Downey boxes, and gives him plenty of opportunity to remind people how talented and versatile he is, but it's not an obviously commercial film. The central character, Dan Dark - called Philip Marlow and played by Michael Gambon in the original - is a man tormented by his demons, which manifest themselves both in the form of horrendously disfiguring psoriasis, and in noir-ish paranoias and surreal song-and-dance hallucinations. He is imprisoned in his hospital room and his despair, with only a shrink called Dr Gibbons - played by Mel Gibson - battling on his behalf, trying to instil some self-awareness in his dysfunctional patient. It's a film about honesty. But it's also a film about ugliness - not something Downey's been known for, has he?

"I have," he counters emphatically. "Right, not physically just behaviourally and spiritually. But you're right, there's something about that... What is psoriasis, except the most obvious and uncomfortable and shameful dermal representation of self-loathing? Gambon nailed it so well: if I can just make it seem like my own misery and rage is more grotesque than what you can see, as plain as the scales on my nose, then maybe we can make this agreement to not talk about what's real, we can stay dishonest, because isn't that what we're supposed to do?"

The project was a gift in more ways than one. "I'd heard of The Singing Detective, but as usual it was Mr Gibson who kind of dropped these tapes in my lap, like he was just dropping by, you know," says Downey. "He always brings some jewel over, like, wrapped in a paper bag just in case I take it too seriously. He was kind of, 'You might want to check these out. You might want to do it.'"

Did he see echoes of his own life in the script? "You know what's so funny is that was really the last consideration. I was thinking more about dumb stuff, like, 'God, do I have to go research film noir?' But as Potter said in his last interview, it's about a man who picks up his bed and walks. Well, of course I can relate to that - but everyone can, you know. What's so great about the story is that it's about someone so deeply influenced by their past, they can't move forward. And all that trash, that betrayal of self and others, makes it seem so impossible."

So has Downey conquered his own demons? "Uuh, yeah. But it's more like, can I do it between now and the time he comes back with that coffee? Can I not be miserable until the latte gets here? That's the thing, the reason that Gibbons/Gibson is really so good, or at least the right guy for Dan, is that at certain opportune times he just comes in and - whack! - just cuts his knees off. He's saying, once in a while 'I'm going to be really brutal with you and it's going to save your ass.'"

It sounds like Gibson may be on a mission to save Downey too, I suggest. "He's wise enough at this point not to have too much attachment to his ability to affect my life in any significant way with regard to something that's so personal. But he's been able to walk the walk, sure." He talks people into letting you work? "He goes one step further and says, 'Let's not even bother, let's stop wasting time. He's either going to fuck everything up, or he's going to do everything fine, or something in the middle. So it's my company, it's my dough - well, it's my company, it's their dough - but it's my call.' He said, 'I'm putting all my eggs in your basket.' And it was fine. I'm actually less of an insurance risk than anyone else on the movie, because anyone can get in a car accident, or someone who they don't know may be struggling with drugs or alcohol and come out of the closet after hump day (when too much money has been spent to cancel the project) and blow the whole movie."

Downey manages to be both sheepish and defiant about his image as a hopeless addict: "I know it only has so much of a shelf life, but sometimes I'm a little embarrassed that it's still so evident," he admits. "Because I could name half a dozen people who had that process occur, maybe not to the extent that I did, but certainly personally it was as much of a drama - and it was known about. And now that it's been behind them for X amount of years it's not even... it would just be a waste of press for them to go there. But for me it's something that lingers, both in the concerns and the support, or the pessimism, or the hopes or the fears of the public. And, you know, I'm a member of the public too, I want to know, 'Who's that guy kidding? He's full of shit probably, he's an actor!' But the idea that I'm just an actor who was a drug addict, who is a recovering drug addict - that's just one spoke within the wheel. It's the one that can take all the other ones out, but it's just another spoke, and it's kind of tight right now, it's not all loose and wobbly. That's the main thing. Believe me, I wouldn't be here at noon on Monday with my clothes matching, being able to hold this cigarette so I can light it, or being here with you instead of in the bathroom doing what's really important."

Does he feel he's been treated unfairly because he's a celebrity? "I would use the word unfair, except that would be unfair to the word," he says earnestly. "And I would use the words 'just because I'm a celebrity' except you know what, that's not true either. The truth is, I created this, I brought this to the public's attention. I did everything that I did, knowing the way mirrors work, knowing the way the smoke blows. It's not like I was capitalised on by a dark, evil society; it's that I unleashed myself on an unsuspecting public, and they reacted... however they did, which is, 'you fuck' or 'aw, we care,' when the truth is just..." Stumped, he turns back to Potter. "Like Dan Dark realises. He so despises that idea of support, of coming back from the illness, from people wanting you to be okay, from your ex-wife actually not having a dark twisted intent under everything she says and does, she's just there, she's human and she loves you and you've been an asshole. That's what's happened." He starts laughing suddenly.

Downey is briskly positive about all this - as only a Californian therapy veteran can be. No wonder: it's his last chance to prove that he's employable, and he's blown final chances before. Like in 2000, when he walked out of jail and straight into Ally McBeal, made a huge impact, but then went straight back into big-shot cokehead mode and got himself arrested and sent back to rehab. Was taking the job a mistake?

"As Elvis Costello would say, it was a brilliant mistake," he laughs. "I never expect to have an impact on anything, except perhaps a brick wall at 100 miles an hour. So it was cool again, I mean where had I been? I'd just gotten out of the pen. I wasn't thinking about me and Ally McBeal, I was thinking, 'Dude, I've got eight pairs of pants. Let's go to the gym, I look good, everyone likes me, where's all this pussy?' And what happened, you know? One more time. Down the torpedoes. It was all set up to be mutually beneficial, it was only my inability to see the truth of what job one was that sent me down off the wrong tracks again. If I wanted to blame, we could start this interview over again and I could really enjoy myself, but I'd just waste both our time." He pauses for the punchline. "But do you wanna?"

That joke seems to be a good sign. Downey may have carried the sins of the Hollywood tribe out into the wilderness but - perhaps because he was so very talented and charismatic, perhaps because he self-destructed so publicly and decisively - he may yet manage to sneak back in through the city gates. So where does he go from here? He's looking at producing as a future career, leading a quiet life, spending time with his ten-year-old son, staying out of the party loop. "I live in Malibu, which is Hollywood, but kind of away from it," he says. "There's the part of Malibu where everyone lives who can afford to live in that part, and there's a part further north where everyone who wants to be kind of isolated lives. Then there's a bunch of places in between where you can actually live if you're not one or the other. And I'm not one or the other. Used to be, but it almost killed me."

Has he made a new set of non-drug friends? "Yes, but do you ever notice that the whole new set of friends you have to make are just going back to the first two or three good ones that you ever had? I don't have to look outside of my family - we could start our own treatment facility, just with the people in my own bloodline who've all been through the same stuff. And everyone's all right, we haven't lost a soldier yet."

And then there's music. Downey is hatching a plan. "I like singing and I'm good at it. That's valid and real - I'm not trying to be something I'm not, that's part of who I am. I write music and I've composed for 21 years now, and that's something - I don't want to say unrequited, but maybe underdeveloped. I'd like to branch out into something more authentic, more autobiographical. And you know," he adds, gazing out of the window, "I feel like I've got nothing but time now."

"I recognise my saints as often as not by them pushing me out
of my chair and making me write their name on my arm."

d o w n e y u n l i m i t e d . c o m