LONDON, UNITED KINGDOM - 2015:  In this Handout image released by Buckingham Palace on April 20, 2016, (L-R) Prince Charles, Prince of Wales, Queen Elizabeth II, Prince George and Prince William, Duke of Cambridge pose during a Royal Mail photoshoot for a stamp sheet to mark the 90th birthday of Queen Elizabeth II in the White Drawing Room at Buckingham Palace in the summer of 2015 in London, England. (Photo by Ranald Mackechnie/Royal Mail/Getty Images)