From numbers theory ('Pi') to drug addiction ('Requiem for a Dream') to time travelling romance ('The Fountain') and sporting machismo ('The Wrestler'), Darren Aronofsky's film choices have never been obvious but have always sucked viewers in with compelling characters and striking visuals. Now he's turned his attention to ballet with the psychological thriller 'Black Swan'. He talks about making the film and his star, Natalie Portman.

When did you first embark on 'Black Swan'? Where did the idea come from?
Darren Aronofsky:
My sister was a dancer growing up and she was very into ballet. It wasn't really anything that I understood. But as I got older, I was thinking about worlds to set films in and I thought ballet could be an interesting world to explore. In addition, I was very interested in Dostoevsky's 'The Double', which is a story about a guy who wakes up and his double is there, and the double starts to replace his life. Then I went to see a production of 'Swan Lake', which I thought was just a bunch of girls in tutus. I didn't know what it was. But when I saw that there was a Black Swan and a White Swan, played by one dancer, and it was kind of a Eureka moment, it was like: 'Oh wow, a double...' So then it started to come together.

How long ago?
DA:
I met with Natalie [Portman] eight or nine years ago. We met in Times Square and had a coffee and I had this idea for something set in the ballet world. It was slowly evolving over the years and it finally came together after 'The Wrestler'. I was working on it with Mark [Heyman, screenwriter] and it was a very hard script to finish because understanding the ballet world was really complicated.

Did the ballet world welcome you? What was their reaction?
DA: They are very insular. Usually it's like: 'Oh, you want to make a movie? Sure!' But they're not like that. They were very indifferent and very unfriendly. It was really difficult to get into that world.

Why is that do you think?
DA:
They really don't care about movies. It not their art and it doesn't seem like they are interested in it. It's some type of popular culture thing, I guess. I don't know. They are really focused on their ballet: they live, breathe, die by ballet. Well, maybe not die, because they all retire at a young age, but even then, they end up being involved teaching and all that stuff.

So how did you convince them?
DA:
There were people that were kind of interested - some dancers, some disgruntled dancers and some major stars. We eventually started working with Benjamin Millepied and Benjamin is deeply respected in that world. He's a principal dancer with the New York City Ballet. He's one of the youngest, hottest choreographers and he has a lot of interest in film. He opened up so many different doors for us and got us into a lot of places.

Natalie Portman has said that it was a very physically and emotionally demanding role. And you were the guy who had to push her. Were there any times when you worried about her on set?
DA:
You don't really need to push Natalie that much because she's incredibly hard working, disciplined and present. She is willing to go for it and rarely complains. She's tough. She's a tiny little girl but she's built of some strong material and she really went for it, over and over and over again. She was very prepared so I didn't really need to push her that much emotionally and she did the physical training as well. She was incredible because it was a very hard role for her.

How much of the dancing did she do herself?
DA:
She did most of it. She was up on pointe a lot. The closing shot of the opening sequence when she goes off into the light is her. A lot of these dancers have been training since they were four-years-old so their bodies have changed, the turnout and the muscles and the bones have actually changed, so there were wide shots where it was clear she wasn't the dancer, but so much of the dancing is her. When she's on top of the ramp and the camera pulls down and the blood comes out and she's on pointe that's her. She really was pretty impressive.

How did you approach the music for the film? There's obviously Tchaikovsky and then you seem to have layered more on top…
DA:
Well, it's not purely Tchaikovsky. It's Tchaikovsky via Clint Mansell, my composer. When I started this film I turned to Clint and said: 'I'm doing this movie for you'. And he took Tchaikovsky and he pulled it apart - because if you just put Tchaikovsky over the movie it would be way too up and down and too fast. Classical music is not movie music.

So Clint took certain themes and ideas and turned it into scary music, so it flows out of Tchaikovsky into Clint, influenced by Tchaikovsky and back into Tchaikovsky. Even the dance club music - the samples and manipulations by The Chemical Brothers and all these bands - are using pieces of Tchaikovsky to make that music. So Tchaikovsky is there throughout the entire film but it's not purely his music. It's exciting and it's fun.

You use mirrors a lot in the film. Is that something you picked up from the world of ballet?
DA:
There are mirrors everywhere in the ballet world because ballet dancers are constantly looking at themselves, and studying themselves, and maybe even judging themselves - all the time. So it was clear to me that the mirror was a major character in this film. The film is also about doubles and your reflection in a mirror is a double, so mirrors became a really important part of the film. From very early on we started to think about all the very different types of cool tricks we could do with mirrors. We tried to have as much fun as we could with them.

What about the feathers growing out of Natalie's skin? It's a very striking image. When did you come up with that idea?
DA:
The story of 'Swan Lake' is during the day she's a swan and at night she's a half swan and half human creature, so it's a werewolf tale. So I was excited to make a were-swan movie (laughs). Then I had the idea of taking Natalie Portman and turning her into some type of creature, which was even more delicious fun. So, that just became a major part of the film.

Did you think about any Roman Polanski films when you were making this movie?
DA:
Yes, of course. 'Repulsion' was a big influence, and 'The Fly'.

Natalie studied psychology at university. If she were analysing you what would she find in your head?
DA:
I've got no idea, probably a lot of gibberish and stuff (laughs). When I watch the film I think: 'Wow, there is a lot of whacked out stuff going on'. (laughs).

Has making the film given you a passion for ballet?
DA:
Yes. I would go to a good performance - if the Bolshoi comes to New York, or if I am in Russia, I'll definitely go see it.

Did winning the Golden Lion at the Venice Film Festival with 'The Wrestler' change a lot in your career?
DA:
I don't think so. I'm still making films out of America so most people don't unfortunately know that much about European prizes and I don't think it matters to them too much. I didn't get a call from the President or anything. I think it might have been Bush at the time so I'm kind of glad, but I would have liked a call from Obama (laughs).

You've had good times and bad times at Venice, so were you nervous about taking 'Black Swan' there?
DA:
If you're talking about 'The Fountain', I had a great time and the audiences were great. Critically, I had some schmucky reviews that are being proved wrong as time goes by - it's like a good bottle of wine that was opened too early. And two years ago (with 'The Wrestler') was just insane. We were completely under the radar, we were one of the last films in the festival and we had no expectations and everyone was like: 'Mickey Rourke wrestling? Are you crazy?' And then it happened and it was insane.

And this time, for 'Black Swan', I wasn't that nervous, even though it was opening night. But then they sat me next to the President of Italy, who was eighty-something-years-old, and his wife was right next to him and I'm thinking: 'Oh my God, this film has ecstasy, lesbians, rave, self mutilation...' So I bent over and I said: 'I'm really sorry for what's about to happen. It's really an upsetting movie, and I don't know what to say'. And he said: 'Don't worry, I will try not to feel any emotion'. And then at the end of the film I turned to him and he said: 'I tried but I felt emotion'. So it was a good victory for me (laughs).

'Black Swan' is in cinemas now.