LONDON, UNITED KINGDOM - FEBRUARY 11: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge wears the Nizam of Hyderabad diamond necklace as she attends The Portrait Gala 2014: Collecting to Inspire at the National Portrait Gallery on February 11, 2014 in London, England. (Photo by Max Mumby/Indigo/Getty Images)