A nude picture of Madonna is expected to sell for thousands at auction.

The photograph was taken for but never used in the singer's controversial 1992 book 'Sex' - in which she posed for a series of X-rated photographs - and will go under the hammer at Bonhams' auction house in New York next month for an expected ￡5,000.

The snap, taken by photographer Steven Meisel, shows a topless 32-year-old Madonna reclining in bed while smoking a cigarette.

The sale will come as a blow to the 53-year-old pop superstar who has previously claimed she has never been able to put the erotic tome behind her.

She said: "I hope that's not the only thing that I'm identified with - taking my clothes off. I have done other things. There's a lot more to Madonna than taking your clothes off."

However, she has also defended the book as a part of her "development" as an artist.

Madonna previously said: "When I published 'Sex', that was a subject that I was interested in exploring. And to me they're both reflections of who I was and who I am now. It's a, you know, kind of development of me."