At the naming ceremony for HMS Glasgow on Thursday, May 22, Kate Middleton struck a nautical note in a navy piped dress that took a page right out of Princess Diana's fashion playbook. In a sophisticated coat dress with white trim by Suzannah London,

The royal headpiece is the one Kate has worn the most during her royal life and was also a favorite of her late mother-in-law, Princess Diana, who wore it on multiple occasions. According to the Court Jeweller, the special tiara is more than 100 years old and was originally commissioned from the jeweler Garrard by Queen Mary in either 1913 or 1914.