LONDON, ENGLAND - FEBRUARY 16: (EXCLUSIVE COVERAGE) A member of staff poses with a 1992 Catherine Walker green silk velvet evening dress with velvet and diamante buttons worn for Diana's Vanity Fair photo shoot with Mario Testino in 1997 during a preview for the forthcoming 'Diana: Her Fashion Story' exhibition at Kensington Palace on February 16, 2017 in London, United Kingdom.On August 31st this year it will be 20 years since Princess Diana died in a car accident in Paris. As part of the events commemorating her life Kensington Palace are showing a number of her dresses in a new exhibition 'Diana: Her Fashion Story' which opens to the public on February 24th. (Photo by Carl Court/Getty Images)