The Duchess of York is to pose for a charity book wearing only a pair of Jimmy Choo shoes and jewellery.
The Duchess will help the Elton John Aids Foundation
She has agreed to be among the famous faces appearing in the book Four Inches.
Money raised from sales will be donated to the Elton John Aids Foundation.
The book - which takes its title from the height of the heels worn by the models - will be out in the spring.
A spokesman for the Duchess confirmed she was "absolutely taking part".
But The Sun newspaper responded rather uncharitably on Saturday by unveiling a readers' petition - entitled "Keep 'em on, Fergie" - in a bid to stop the duchess revealing all.
Fashion photographer Pamela Hanson took pictures for the book, published by London-based Scriptum Editions.
Other big names thought to be posing for shots are models Kate Moss and Rachel Hunter, and actresses Rebecca Romijn-Stamos and Lara Flynn-Boyle.
A spokesman for Scriptum said: "It features women of various fame in Jimmy Choo shoes and Cartier jewellery. We are still shooting the book."
The Elton John Aids Foundation has refused to release full details of the project.
A spokesman said: "It is a photographic project - it is not just a book. The book is just an element of the whole project."