Britain's Prince WiIliam, the Duke of Cambridge, (L) and his wife Catherine, Duchess of Cambridge, leave the King Edward VII hospital in central London, on December 6, 2012. Prince William's pregnant wife Catherine left a London hospital on Thursday, four days after she was admitted for treatment for acute morning sickness.
Catherine, Duchess of Cambridge (C) takes part in a day of activities and festivities to mark the occasion of St Andrew's Day at St Andrew's School on November 30, 2012 in Pangbourne, Berkshire, England. The Duchess visited the Pre-Prep School for under-5s, unveiled a plaque to officially open a new artificial turf playing field and met members of the school's hockey team, which she played for during her time as a pupil at the school (1986-1995).
LONDON, ENGLAND - JANUARY 08: Catherine, Duchess of Cambridge attends the UK premiere of War Horse at the Odeon Leicester Square on January 8, 2012 in London, England. (Photo by Ian Gavan/Getty Images)
Prince William and his new wife, Catherine, Duchess of Cambridge, climb aboard a plane of the Royal Canadian Air Force at London's Heathrow Airport, heading to Ottawa, Canada on June 30, 2011. This 12-day North American tour marks their first overseas trip as a married couple.
Catherine, Duchess of Cambridge, donned a striking wide-brimmed hat with flowers at the back for the wedding of Prince William's cousin, Zara Philips, at Canongate Kirk in Edinburgh, Scotland on July 30, 2011.
Catherine, Duchess of Cambridge, wore a smaller but still eye-catching hat to the Epsom Derby. She sits between her brother-in-law, Prince Harry, left, and her husband, Prince William, right, at Epsom Downs racecourse on June 4, 2011.
Catherine, Duchess of Cambridge, was one of many royal women wearing hats to the private wedding of Prince William's cousin, Zara Philips, to rugby player, Mike Tindall in Scotland. Kate's hat was by far the largest with a simple brim in the front and an elaborate floral design at the base of the hat.
Prince William and his wife, Catherine, Duchess of Cambridge, helped at the Mission Serve: Hiring Our Heroes event in Culver City, California on Sunday, July 10, 2011, which was their last day on their tour of North America.
Catherine, the Duchess of Cambridge, appears much thinner than she did before the royal wedding, just weeks before this meeting between the newlyweds and US President Obama and First Lady Michelle Obama.
Kate was so proud of her husband's team winning the polo challenge that she kissed him on stage, which is rare to see from the private newlyweds. Meanwhile, Will's teammate and fellow champion, Santi Trotz, teased the couple by sticking out his tongue.