Britain's Catherine, Duchess of Cambridge (L) and Prince William, Duke of Cambridge (R) attend the ceremonial welcome ceremony for Singapore's President Tony Tan Keng Yam at the start of a state visit at Horse Guards Parade in central London on October 21, 2014. Singapore's President Tony Tan Keng Yam began the first full day of engagements in the first state visit by a Singaporean president to Britain. AFP PHOTO / POOL / LEON NEAL        (Photo credit should read LEON NEAL/AFP/Getty Images)