LONDON, UNITED KINGDOM - NOVEMBER 21: Prince William,Duke of Cambridge laughs as he is introduced as the Duke of Edinburgh by Master Of Ceremonies, Richard Birtchnell as he visits RUSI (Royal United Services Institute) to present the Chatham House (The Royal Institute of International Affairs) Prize 2014 to Melinda Gates in the Banqueting House on November 21, 2014 in London, England. (Photo by Arthur Edwards - WPA Pool/Getty Images)