The only copy of Sean Penn's first novel has been destroyed in a fire, according to reports.

The actor, who won an Oscar for his performance in Mystic River, had spent months working on the manuscript.

He said: "It was written on an old typewriter and I had all the pages on my desk but they burned in a fire."

Penn's directorial outing Into the Wild, which is based on the true story of American wanderer Chris McCandless, recently opened to positive reviews in the US.