WARSAW, POLAND - JULY 17:  Prince William, Duke of Cambridge, Catherine, Duchess of Cambridge and Poland's First Lady Agata Kornhauser-Duda attend the Queen's Birthday Garden Party at the Orangery, Lazienki Park on day 1 of their official visit to Poland on July 17, 2017 in Warsaw, Poland.  (Photo by Julian Simmonds-Pool/Getty Images)