The actor talks about his new film, plus gives us the lowdown on the new David Fincher film.

Robert Downey Jr. had us all in stitches. He's a pretty funny guy and had no problems having fun during the interview. I don't think I've ever had to edit out this many expletives from an interview. A Scanner Darkly was a labor of love for him. We didn't get too into his past, and the relevance of drug use as a motivation, but it seemed understood. Robert took the film seriously and had nothing but praise for Richard Linklater and his creative vision.

Robert Downey Jr: I got a call, I read the script, and I thought, this is nuts, this is going to be cool. And Keanu was playing the lead, so I went to the chateau, and we just started to have this spit ball session. We talked about the characters and all that. And Woody, and Winona, it was just a great experience for me.

Was working with Richard Linklater also a draw?

Robert Downey Jr: I saw School of Rock, and I was like, why haven't I worked with Richard Linklater already? Then by the time I got him I was like, I'm really pissed off I feel like you owe me some retroactive swag. He gave me the 10-year anniversary "Dazed and Confused" T-shirt, which I still wear with relish.

Would you have made it without Linklater?

Robert Downey Jr: It would have had to be someone real special, and I am convinced that he is one of our great American directors.

What was the rapport like on set? Did everyone share the same vision of the film?

Robert Downey Jr: I would say that Rick and Keanu got it, that Winona looked great and is a great actress and really smart, and Woody and I were basically in a scenery chewing contest. At one point I shoot off this silencer, and I hear a thud. I go, did he just fall out of a tree? Without a crash pad or anything? What is he trying to do, this is my scene! I look over and he's, "that's lunch."

Did you ever think about being animated?

Robert Downey Jr: I kind of forgot to tell you the truth. I forgot and then I was really pleased. It's the greatest smoke ring blown in the history of cinema.

Did you get to see any of the live footage? Could that have been released as the film?

Robert Downey Jr: It looked really simple and crude and improperly lit, which it was, but it also would have sufficed.

Is it easier to shoot a film without worrying about lighting, hair, make-up etc?

Robert Downey Jr: Yeah, isn't it great? I gave myself a really bad haircut a week before we started. The missus was like "wow! What the fuck? You cut your hair yourself! You look crazy." Body mikes would fall out. Things would fall on the table and be in frame.

Did you enjoy the process of making it?

Robert Downey Jr: It was fantastically fun. I'll go back to it as a period in time, it was in Austin, we were all staying at this hotel. Woody wouldn't put on the air conditioning, Keanu had his bass in the next room, Winona was like, "guys, you want to go to a movie?" I was like, no, I want to make a fucking movie! I went to workout when I wasn't on set. I treated it like it was boot camp.

What was your reaction to the final product?

Robert Downey Jr: I had a really emotional reaction to seeing the movie at Cannes, because it's touching and personal and it's Dick's story. But it's science fiction, it's got this generation of actors, except for maybe Keanu, we haven't gotten through the last ten years all in one piece.

That bicycle scene is absolutely hilarious. Was that verbatim from the script?

Robert Downey Jr: I just kept looking at it and saying my lines, following the logic of the scene with someone who's obviously wrong, but is very excited about how great things are. Then his life crashes before his eyes and he pulls everyone else in. He condescends to people.

Do you read anything into the subject matter? Are we really being manipulated?

Robert Downey Jr: You have to give credit to any institution that's so evil that they're completely running the program. I'm not a big Illuminati guy. I think paranoia goes from generation to generation. It's convenient to imagine that there's a few people controlling everything, that way it's manageable and small. But that's not life, life is messy.

Is there thought to your character's logic processes? Or is he just unnecessarily paranoid?

Robert Downey Jr: If you're anything like me there are days when you're convinced you know more than everyone around you. Which is often confirmed by your interactions with people. I know if you talk faster and use more ten-dollar words than everyone around you, you convince half of them that they should shut up because you know what you're talking about. I think Dick [Linklater] was really fantastic at throwing up a stereotype or an archetype, better yet, and then throwing why it's full of holes.

Do you think that this film is made at a time when its message is particularly relevant?

Robert Downey Jr: Yeah. Every frame and every instance of the film is supported by - I'm not big on this word- but the karma of the people who came together. This film, ten years ago would have meant one thing. It's just seeing cycles, and having been around enough cycles to understand that I'm playing the school principle instead of the rebel student, things tend to repeat themselves in a way that's predictable and yet exciting.

You just wrapped Zodiac. What was it like working with David Fincher?

Robert Downey Jr: He's very tough on technique. So if you're a technically proficient actor, you're going to survive. If you're not, you're going to hate him.

Why make films like A Scanner Darkly and Zodiac, but also do The Shaggy Dog?

Robert Downey Jr: I just wanted to be in a Disney movie and they offered it. Best job I ever had. The craft service is amazing. Fucking crazy. "Hey, thanks, we got that shot with you and the monkeys, we'll see you in three weeks, did you get your check?" I'm like, wow.

What's next for you?

Robert Downey Jr: Zodiac's done, Fur's coming out, I'm doing this movie called Charlie Bartlett in Toronto, which I adore. It's like if Mean Girls was like a "Harold and Maude" type thing. I play a school principle.

A Scanner Darkly is open in limited cities now; it expands nationwide in the coming weeks; it's rated R.