Is it tough playing someone who is so gifted?

Well, the whole character was difficult. Even though he [John Forbes Nash] was famous in mathematical circles in the 40s and 50s, nobody ever thought to put him on camera. I've played real people before but in a more contemporary setting, and I've had more material to go off. I had basically 17 black and white photographs and him as an old man and 35 years of medication in between. To try and construct who he was was a very difficult thing, so we basically started off with very broad strokes - he was born in West Virginia so he's going to speak a certain way, and we went with that. But you're talking about a level of intellect that's beyond the scaffolding of "I know how to do long division or I understand algebra and therefore I'm a mathematician". You have all that, but you have pure intuition. So he's leaning far more towards the thought process of an artist - he can look at a mass of numbers and equations and simply know what the answer is.

Last time I saw a schizophrenic portrayed on the screen was "Me, Myself and Irene" which couldn't be more removed...

Well, the trouble with "Me, Myself and Irene" - although it's a brilliant performance and Jim Carrey's absolutely one of the best and I love his energy and what he did in that film - but it's sort of bending towards the social misunderstanding of what schizophrenia is. It's not about duel personalities, it's about separate planes of reason.

Ron Howard's assembled a great cast. I mean, Jennifer Connelly has never been better, and Ed Harris...

Well, Ed's a fantastic guy, he's got a great energy level - he brings a palate of decisions to even the simplest of scenes which 5,000 actors wouldn't go towards because they're not thinking about the level of information that he is, and the depth. Christopher Plummer I'd worked with before [on "The Insider"], so I got a few more stories out of him about Peter Finch, so he was great. And there's a young Englishman by the name of Paul Bettany, and I think this film will keep him quite busy for a few years.