Small ad: Prominent film director seeks "ordinary bloke" to play the lead in his next film. No experience necessary.

It is not every day Roman Polanski, maker of Chinatown and Rosemary's Baby, throws the door open to an amateur to anchor a £25m movie.

The classified advertisement in yesterday's Guardian was not quite that bald, but not far off. "Acting experience not essential," it said, but the right person "needs to be sensitive, vulnerable and charismatic".

The Actors Centre in Covent Garden, London, where the open auditions for the part of the Polish composer Wladyslaw Szpilman in The Pianist will be held on Saturday week, is already wondering whether it should order crash barriers.

But then this is no ordinary film. For Polanski, 67, who has spawned more than his fair share of myths and horror stories, is confronting his past for the first time.

He was born in Paris in 1933, and his Polish parents moved back to their homeland just as war clouds gathered. As Jews, they were the first to be rounded up and Polanski's formative years were spent amid the horrors of the Krakow ghetto. He survived liquidation by the Nazis only because his father pushed him through a hole in the barbed-wire fence.

While his mother perished in Auschwitz he was sheltered by farmers until he managed to find his uncles. His traumas did not end there. They beat him, and they only thing that kept him sane, he later admitted, were the Nazi propaganda films he sneaked into cinemas to see. He was reunited with his father in 1945.

For most of his adult life Polanski has been obsessed with The Pianist, the harrowing autobiography of Szpilman, who like him narrowly escaped the camps.

The book, published in 1946, tells how he was saved by a German officer who admired his music and his playing.

Alex Johnson, from casting agents Celestia Fox, said because the story was "so close to Polanski's own experience, he has a very clear idea of what he wants. He feels there is someone out there, and not necessarily an actor, who embodies what he feels about Szpilman. Obviously, the ability to play the piano would help, but he is looking at this in a very broad way."

Polanski will not able to attend auditions himself. There is the matter of possible extradition to the US to worry about. The director has not visited Britain since 1978 and is still wanted in Los Angeles in connection with the alleged rape of a 13-year-old girl during a party at Jack Nicholson's mansion in 1977.

Polanski's second wife, the actor Sharon Tate, was murdered by Charles Manson and his gang in California in 1969.

He is now married to the French actor Emmanuelle Seigner, 33 years his junior. They have two children.