It's the perfect formula for Kiss Kiss Bang Bang, now on DVD, in which he plays a dim but good-hearted thief-turned-Hollywood hopeful who serendipitously gets swept up in a noir L.A. mystery. His partners are a gay detective (Val Kilmer) and his high school crush (Michelle Monaghan). Shane Black, the scribe behind the Lethal Weapon movies, wrote and directed the film.

Downey spoke to amNewYork while shooting his new movie, Charlie Bartlett, in Toronto. He also stars in A Scanner Darkly this summer, with Lucky You and Fur coming out this fall.

You and Val Kilmer had a great rapport in the movie. Did you know each other well before working together?

We really didn't. I had been to one of his famous Hollywood Hills parties a couple months earlier, and he'd gotten back from doing, I think, some additional scenes on Alexander. He had the full Macedonian beard but he was wearing a three-piece suit with a tie. It was crazy, and Susan [Downey's wife] -- Mrs. Downey -- said, "My god, he's truly like the most eccentric actor I've ever seen." And I thought, "God, I really should work with this guy some time." And three months later we were cast in Kiss Kiss Bang Bang.

How did you come to get cast in the movie?

I had heard Mrs. Downey reading the script and laughing out loud, which is an uncommon occurrence. The movies she does for Joel [Silver] are like House of Wax or V for Vendetta, all these other kind of more serious genres. And I thought, what is it that's got her laughing her ass off? She said, "Oh it's just a scene where Harry Lockhart … has put his finger in a bowl of ice and then a dog eats the finger. And I go, "Why does he have his finger in a bowl of ice?" She goes, "Well, he got it cut off in the door by this girl he grew up with. But then he goes to the hospital and gets it sewn back on." Then I go, "Well if he gets it sewn back on then why the f--- is it in a bowl of ice?" Then she goes, "Well, Mr. Frying Pan and Mr. Fire tear it off at a party." Then I say, "Oh my God, I've got to read this." So, anyway, it was a little while and they weren't entirely sure. Then Joel just called up and said, "You're doing this movie."

What do you think makes the movie so funny?

I think it's like everybody, men and women alike, wants to be a tough guy or a tough gal sometimes. But most of us just plain aren't and never will be.

One of my favorite lines was when you're talking about shaking the carpet and all the normal girls--

"It's like someone took America by the East Coast and shook it and all the normal girls managed to hang on." Another gross generalization, a blanket statement, but for some reason or other, no matter where we screened this film -- Toronto, New York, Cannes or Los Angeles -- everybody laughed their asses off when they heard it. 'Cause you know, of course, it wouldn't be funny if there wasn't an element of truth.

The film did pretty well with critics, but the minority of critics who didn't like it tended to say it was empty and didn't have a plot. What do you think about criticism like that?

I disagree. But, you know, I've never heard everyone agree on anything. They're probably just not smart enough to follow it, so they just say it doesn't have a plot. It's got a plot, but the plot for this movie is like a Ferrari engine, and if you don't understand anything except Hondas then you're f---ed.

Do you read what critics write?

I don't read it and take it to heart.… They're only people who I don't even know who the f--- they are anyways. It would be kinda like if you got a random phone call saying you're the awesomest ever. What does that mean? I don't know who it is. You get a random phone call saying you're two-dimensional and lame. How does that feel? I don't know, kinda like the first one.

Are there any lines from critics that have stood out?

I haven't really been given many bad reviews, and the good stuff is all almost pretty much the same -- and I'd feel uncomfortable quoting something glowing about myself to you. Oh wait a minute, one time somebody said I looked like Pee-Wee Herman coming out of a coma.

Was that a compliment or criticism?

I think he was trying to be mean, but I thought it was actually very thoughtful and insightful and probably accurate.

Is your movie Poe still in the works?

That is something that somebody posted on some IMDB thing and everyone stalks me on it like it's fact because they saw it on the Web somewhere. I should post some other things on the web. You know, it used to be don't believe everything you read in the news and then it was don't believe everything you see on TV. And now the new one is don't believe everything that's printed on some website that's not even run by the people the website is about.

Almost every article that's been written about you mentions your "troubled past." Do you get regrets about your past? Or do you more regret that you had the misfortune of getting caught and being scrutinized by the media?

Well, I don't know. I mean, sometimes it's fortunate to get caught, you know? No, I've got no regrets today, save for the fact -- it's so funny, I've decided 10 times that it's just so passé to talk about things that have been over for years. But I guess until further notice it's kind of a knee-jerk requirement, like people just have to say, "Oh, what am I forgetting? Oh yes, one more question, your past." It has nothing to do with anything we're talking about today, but you know, just to mix it up. I did answer that question as thoroughly as I felt I could.

Thank you. And what about your music career? I know you released an album a few years ago.

Oh yeah, I got a bunch of other stuff going on. I'm doing a book and I'm putting out two more. I got a musical and I wanna do a bunch of cover songs, and I wanna put out some more original stuff. So, now I'm doing everything I really wanted to do 10 or 15 years ago, but I just didn't have the maturity, for lack of a better word, to kinda put it all together.