Prince William's signature is seen on a copy of the birth register for Prince George of Cambridge, at Westminster Register Office in London August 2, 2013. Britain's Prince William and his wife Kate on Friday registered the birth of their son George, who was born on July 22 in a blaze of global publicity and is third in line to the British throne.[Photo/Agencies]

Westminster city council registrar Alison Cathcart holds a copy of the birth register of Prince George of Cambridge at Westminster Register Office in London August 2, 2013. Britain's Prince William and his wife Kate on Friday registered the birth of their son George, who was born on July 22 in a blaze of global publicity and is third in line to the British throne. [Photo/Agencies]