Lady Kitty Spencer, Princess Diana’s niece, looked stunning at the Estée Lauder Re-Nutriv Dinner, wearing a black strapless dress – very similar to her aunt’s revenge dress from 1994. Lady Kitty Spencer, Princess Diana’s niece, looked stunning at the Estée Lauder Re-Nutriv Dinner, wearing a black strapless dress – very similar to her aunt’s revenge dress from 1994.