The Fabulously Frou Frou Dress That Changed Princess Diana's Style Forever British Vogue 121) March 9, 1981 Lady Diana's first official engagement, wearing "that" Black Taffeta dress designed by Elizabeth and David Emanuel (who also designed her wedding dress). Modal Square Neck Bodycon Midi Dress in Leopard Print L Oh Polly Princess Polly Cheetah Print Dresses Mercari In a new documentary, "Secrets of Diana's Wedding Dress," Elizabeth Emanuel, one of the designers behind the princess's gown for her royal wedding, reveals that she used a code name for Diana