At age 65, prolific filmmaker Werner Herzog shows no signs of taking things a bit easier. Notorious for his gruelling filmmaking style, he's famously willing to put himself through everything he demands of his actors. This led to a series of outrageous on-set experiences with eccentric star Klaus Kinski, which Herzog documented in My Best Fiend, following their often murderous relationship over the years. Herzog is the only filmmaker who has shot features on every continent. His classics include Aguirre: Wrath of God, Nosferatu, Fitzcarraldo, Cobra Verde and Grizzly Man, and he also finds time to act in the films of Harmony Korine. In addition to his film career, he walked on foot from Munich to Paris in 1974, was shot during an interview by journalist Mark Kermode in 2005, and rescued Joaquin Phoenix from a terrible car crash the following year. Now with Rescue Dawn, he returns to the subject of his 1997 documentary Little Dieter Wants to Fly...

When you finished the doc Little Dieter Wants to Fly, what did you think still needed to be said in a constructed narrative?

Werner Herzog: For Dieter and me it was always clear that this was unfinished business. Too many things that are really fascinating - such as what happened in the prison camp - are hardly touched in the documentary. The films complement each other very well. There was also a consensus between Dieter and me that the feature film comes first, but since technically we did it later, interestingly, the film that was not done yet influenced the first film. But in its heart the feature film has always been the first one.

Why did you wait almost 10 years to make the feature?

WH: Well, it was possible to make the feature film only when the money was available. Otherwise I would have done the feature as the first one. But the feature film in that case would have been unfinished business, because we would have seen nothing of Dieter's childhood, nor do we see anything about his life later on, nor do we see the real man. And of course his story was fantastic before he made it to the United States and Southeast Asia, and equally afterwards. He had four more plane crashes that he survived, and children and wives and just totally wild stuff. [Dengler died at age 62 in February 2001 of Lou Gehrig's Disease, and was buried in Arlington National Cemetery in Washington DC.]

How was Christian Bale suited to the role?

WH: The simple answer: He's the best of his generation. And I worked with the best of their generation: Steve Zahn, Christian Bale and Jeremy Davies. So I was blessed with the best of the best. With Steve Zahn, nobody expected anything from him like that because he's mostly been the funny sidekick in Eddie Murphy movies. But I knew that Steve has something very, very special about him.

Did you cast Bale partly because of his reputation with things like extreme weight loss?

WH: Yes, but we had to be careful. Christian always said, "For God's sake, let's not make a great fuss about this." Because he didn't want to end up in the Guinness Book of World Records for starving himself. Of course in The Machinist he lost much more. And what we did was significant and visible for an audience, so that by the end of the film he has quite visibly lost some weight. And that's fine. And we shouldn't make a big fuss about it. It only showed the amount of dedication and professionality of everyone involved. And that's the key to it.

But then Bale's dedication extended to eating maggots...

WH: That's not really incredible. I've seen people in other country eat maggots, and they're very rich in protein. So there's nothing really wrong about it. In our own cultural context we're not accustomed to eating maggots, but Christian Bale always knew I would essentially offer to do things I asked from the actors. For example, when we were in the rapids, I spent all day with them in the water. I offered to eat a couple of spoonfuls of maggots, but in this case Christian said, "Oh for God's sake, just turn on the camera and let me get on with it."



Was it just one take?

WH: That was one of only two misunderstandings. One was when we were a few hundred yards apart and we had to yell over a large distance and something got lost, and for a moment we were angry with each other, but it was over in two minutes flat. And then that moment when he ate the maggots, I had told him, "You are the one who will stop the scene." But while he ate - he probably didn't hear it correctly - he kept eating, eating, eating, and he got kind of angry because I never said cut. So finally when the four minutes of film had run out, and everybody stopped, he said he didn't hear cut from me. And that was the second moment where there was a kind of misunderstanding, but these things pass by so quickly. It's just a little error. But, for example, in solidarity I lost half the amount of weight he lost. It would be counterproductive to lose the same amount because he would gain it back fairly quickly. The real challenge - because we shot the film backwards - was to develop the character backwards. To find the dynamic and the flow was quite difficult.

Why do that?

WH: Well it was a practical consideration. It takes you five or six months to lose weight but you gain it back in two or four weeks. We could have done it the other way around, but then we would have needed five or six months of shooting, and we only had 44 days. And while you are working, he would have to keep starving, starving, starving, until at the end he was very thin. So for practical reasons we had to do it backwards. Christian has been such a disciplined man. Jeremy Davies in a way overdid it. He's quite thin, but he arrived in Thailand with quite a few very large suitcases, and it turned out they were filled with bottled water, Evian in plastic bottles. And in Thailand, right next to the hotel in the supermarket you could have bought the same ones. But he brought all his water along - he was totally wild. He ate very, very little and mostly only drank water, and that was that.

Can Christian play any character? Do you think he could even play Kinski in a biopic?

WH: No, that would be ridiculous! He couldn't do it - no, because Kinski was kind of unique and you can't even imitate him! Not anything. It would be wrong for him to do, for example, Kinski. Or it would be wrong for him to do Mohammad Ali. In a way I had to stop Christian from going into too much of an imitation of the real Dieter Dengler. The real Dieter Dengler had a very thick German accent, and Christian and I were quite clear: we had to dismiss that. We did not try to imitate that - just a slight hint of an accent. Christian kept saying to me, "You as a crowd won't even hear it!" It's so subtle. I think he could do pretty much anything, but he shouldn't do everything. In essence, yes, but you do not imitate idiosyncrasies and actions in the same way as, for example, when you make a film about Mohammad Ali, you have to be a rapper, like Ali, and you have to dance in the ring, and you have to be like him. And Richard Nixon - you have to look pretty much alike, and you have to speak like him and move like him.