LONDON, UNITED KINGDOM - JULY 23:  Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge, who is holding their newborn son, depart the Lindo Wing of St Mary's Hospital on July 23, 2013 in London, England.  Catherine, Duchess of Cambridge yesterday gave birth to a boy at 16.24 BST and weighing 8lb 6oz, with Prince William, Duke of Cambridge at her side. The baby is third in line to the throne and becomes the Prince of Cambridge.(Photo by Anwar Hussein/Getty Images)