LONDON, ENGLAND - OCTOBER 21:  Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge greet the President of Singapore Tony Tan Keng Yam and his wife Mary Chee Bee Kiang at the Royal Garden Hotel on the first of a four day state visit to the UK on October 21, 2014 in London, England.  (Photo by Anthony Devlin - WPA Pool/Getty Images)