SYDNEY, AUSTRALIA - APRIL 20:  (NO UK SALES FOR 28 DAYS)  Prince William, Duke of Cambridge, Catherine, Duchess of Cambridge and Prince George of Cambridge visit the Bilby Enclosure at Taronga Zoo on April 20, 2014 in Sydney, Australia. The Duke and Duchess of Cambridge are on a three-week tour of Australia and New Zealand, the first official trip overseas with their son, Prince George of Cambridge.  (Photo by Pool/Samir Hussein/WireImage)