Diana's Dresses: Diana, Princess of Wales wearing a full-length long-sleeved evening dress of peppermint green silk by Catherine Walker, with broad horizontal stripes over the bodice and sleeves, at the premiere of "Accidental Hero" in London in 1993. The dress is part of a collection of 80 ballgowns belonging to the princess that will go under the hammer at Christie's in June. The charity auction, said to be the idea of her elder son, Prince William, will be held in New York on June 25, with proceeds going to the Royal Marsden Hosptial Cancer Fund and the Aids Crisis Trust. PA. SEE PA STORY ROYAL Diana. Photo by Martin Keene.