Britain's Queen Elizabeth II (L) and Britain's Prince Philip, Duke of Edinburgh pass a giant photograph taken to be used as part of a series of 10 Royal Mail postage stamps, to mark the monarch's 90th birthday, during her tour of the Royal Mail Windsor postal delivery office in Windsor, west of London, on April 20, 2016, to mark the 500th anniversary of the Postal Service. Queen Elizabeth II is set to celebrate her 90th birthday on April 21, with a family gathering and a cake baked by a reality television star, as a new poll finds Britain's longest serving monarch is as popular as ever. The queen has reigned for more than 63 years and shows no sign of retiring, even if she has in recent years passed on some of her duties to the younger royals. / AFP / POOL / Chris Jackson (Photo credit should read CHRIS JACKSON/AFP/Getty Images)
