Geoffrey Rush: I did not want to do it. I read it, thought, this is great, and promptly handed it back. I did not want to put myself on the line, as an Australian playing Britain's greatest comic actor. The fans of Sellers are obsessive, possessive - and aggressive. I did not want to risk their anger - or my own reputation.

Geoffrey Rush: Vanity - my own. I was approached again, about a year after I had refused it, by the director Stephen Hopkins. He said: "We have asked no-one else - you are the only actor who can do it." He picked a time when I was making Pirates Of The Caribbean and I thought: "Yes, I am ready for something more serious again". But the moment I started preparing for the role, I felt that I should have stuck to my original refusal.

Geoffrey Rush: You can start with the fact that I am tall and thin and he was short and pretty chubby and very hairy. I was also an Aussie. And I was also something of a fan, having heard him in The Goons, which was played on lunchtime radio - years after they were made - when I was getting ready to do matinee theatre. So it was the voice, the looks, the culture, the fact I was in awe - take your pick.

Geoffrey Rush: I spent weeks with the voice coach, Barbara Berkery, who had worked with Gwyneth Paltrow [on Emma] and Renee Zellweger [on Bridget Jones's Diary]. Sellers did not have just one voice - he changed his accent as he became more successful and thinner. He must have had about six voices of his own throughout his career. Then there were the voices he used for his film characters, which I had to get right, too. There was also some more material when we see Sellers mimicking other people, like the director Blake Edwards (John Lithgow) or his mother, Peg (Miriam Margolyes).