Lady Kitty Spencer wore a plunging black dress at the party in aid of the Chelsea Flower Show. Princess Diana’s niece wore a stunning black dress with Dior accessories as she posed with Sam McKnight, Diana’s hairdresser. Lady Kitty Spencer wore a plunging black dress at the party in aid of the Chelsea Flower Show. Princess Diana’s niece wore a stunning black dress with Dior accessories as she posed with Sam McKnight, Diana’s hairdresser.