Here's your princess. The Duchess of Cambridge turned up her royal wardrobe by wearing a tiara to the annual Diplomatic Reception at Buckingham Palace tonight with Prince William , the fourth time we've ever seen her wear the regal piece. It's the Lover's Knot tiara, which belonged to the late Princess Diana , and was gifted to Wills' mother from Queen Elizabeth II on her wedding day in 1981 to Prince Charles This is the first time anyone has worn the piece since Diana's tragic death in 1997. Princess Diana RELATED VIDEOS: This content is available customized for our international audience. Would you like to view this in our US edition?