Good Night, and Good Luck director George Clooney produces and stars in the hot new political thriller Syriana, about the ins and outs of the global oil business. In this interview, the Hollywood virtuoso talks to Street about his experiences filming the flick.

What political message is being conveyed in Syriana?

Although I've certainly been outspoken at times politically, I thought it was important between Good Night, and Good Luck and Syriana, both films, that the idea was not to be political necessarily. Obviously it's a political film, but we showed this to a lot of neocons who liked it and agreed with it. Our argument, of course, is to raise a debate, not to tell people what the answers are, because clearly we don't have any answers for this -- the issues or the problems.

How was it making the transition from your previous characters, who are sort of charming, charismatic, like Danny Ocean to the semi-under-appreciated Bob Barnes?

Well, it wasn't so hard. I'm fairly familiar with the guy. I spent a lot of time with Bob Baer, the real CIA guy. So the transition was mostly about making sure that there weren't any elements of Danny Ocean in this character. The way you do that, first of all, you do it changing physically, and then you spend a lot of time with the real guy to understand why he's so disenchanted with his role at the CIA and how he feels deserted, and then you sort of toss that into the mix. So it's a little bit of everything, a lot of information and a little bit of shaving your hair back.

What did they do?

I think the debates in general are what are we going to do with some of the situations, like if you're going to have a war against an idea, which is terror, then you have to understand the elements. You can't just say they're evil. You have to understand what makes them do evil things. It's the same discussion we had when we were making Good Night, and Good Luck too, which was the basic idea is the only thing that we were saying was we weren't going to be told that we can't dissent or ask questions. We're not going to be called unpatriotic for asking questions. That was the one element of that that we thought was important. We've had some success with that. In terms of politically, this is as much an attack on 50 or 60 years of flawed policies in the Middle East. This isn't something that happened in the last four and a half years. So in general, we certainly weren't making this as a "Go get Bush" thing. It was much more of a "Let's talk about some real problems," some fundamental problems with our addiction to oil.

You had to gain approximately 30 pounds in 30 days to play the role of Robert Barnes. I was wondering how difficult it was for you to transform into this character.

The truth is it's not nearly as fun as it sounds, the idea of putting on that kind of weight, but at the end of the day, in general, that's what we do for a living. So my job was just to eat as fast as I could, as much as I could, because we had wrapped Ocean's Twelve I think in early August, and in early September we started shooting the movie. So I didn't have a whole lot of time. But mostly you just ate until you wanted to throw up, and made sure you didn't throw up. So that was my job for a month, eating.

I read somewhere that you got a spinal cord injury on the set. How exactly did that occur?

It was my own dumb fault. I was taped to a chair and a guy was pretending to hit me. It's all fake, you're not really getting punched, and I flipped myself over on the chair, and cracked my head and tore what's called my dura, which is the wrapping around your spine, and ended up with what they call CSF leak, which is a cranial spinal fluid leak -- good fun. I highly recommend it for everybody out there.

What [was] the hardest scene for you to shoot?

In Syriana, the hardest obviously was me getting tortured. The problem was that I got injured along the way. I thought I had an aneurysm. It was a long, drawn out couple of days of sitting in a room taped to a chair and getting buckets of water, which isn't in the film anymore. There's a lot more torture to it that you don't see, sort of like what we're doing in the administration. Just kidding. But anyway, I think that was by far the toughest scene to shoot. But it should have been; it was designed to be that way.

Any personal anecdotes that you could share, [about coming] in contact with some of the non-American cultures during the making of the film?

I wouldn't say shocking, but I would say it's always eye-opening, because it's important, I think, for everyone to travel, to get points of view of the rest of the world. It is always eye-opening to understand how many people are mad at us over some of our actions. I remember sitting there on the roof of a building in Casablanca. It was during Ramadan. A siren would go off and everyone would get out of their cars and face Mecca and pray in the middle of the street. There were hundreds of people, as far as your eye could see. I remember sitting there watching that and thinking anyone who thinks that they have the religious hierarchy over anyone else should be standing here looking at these people, and understand that they have a very strong belief in what they are doing, as well.

In Syriana you acted, and in Good Night, and Good Luck not only did you act, but you also directed. Which tickled your fancy more, directing or acting?

I'll tell you, directing you get to be the boss all the time. In acting you have to listen to the director. So it's fun to be the boss. By the way, directing is something you can do when you get old and fat. So, believe me, directing is the way to go. All kidding aside, it's actually a very creative place to be. Writing and directing was one of the most creative times of my life, so I enjoyed that a lot. Only if you can do stuff you dig though -- I think it would be really miserable to be directing something you hated, because it takes a long time. It's a year and a half out of your life, no matter what you do.

There's a big ensemble in this movie; how [do] you approach a film, when it's an ensemble as opposed to being the leading man?

I think every movie I've ever been in is an ensemble. Unless you're doing a one-man show, I think it's an ensemble. So I've never really thought of things as a lead or not a lead, and you don't really change the approach. I've had all of my great successes in things that are famous ensembles. ER is easily the biggest success I've ever had in my life, and that was famously an ensemble. So I don't think you really change anything. You just carve out little places for you to do your thing and watch other people be really good.