Designer Catherine Walker was an enduring favourite of Diana, and while a lot of her gowns from the '80s look dated now, this one, worn to the Cannes Film Festival in 1987, looks very similar to styles we see on the Croisette now. The dress featured a gathered crossover detail that hugged the waist and a matching stole that fell down the back. Many consider it one of the best Cannes looks of all time, the perfect combination of romantic and elegant. It was also a very carefully chosen colour, complementing Diana's blue eyes perfectly.