LONDON, ENGLAND - JUNE 15: Prince William, Duke of Cambridge during the annual Trooping The Colour ceremony at Horse Guards Parade on June 15, 2013 in London, England. Today's ceremony which marks the Queens official birthday will not be attended by Prince Philip the Duke of Edinburgh as he recuperates from abdominal surgery and will also be The Duchess of Cambridge's last public engagement before her baby is due to be born next month. (Photo by Mark Cuthbert/UK Press via Getty Images)
Britain's Prince William
Britain's Prince William, the oldest son of Princess Diana and Prince Charles, turned 31 on June 21. The prince, also known as the Duke of Cambridge, is expecting his first child with wife, Catherine Middleton.