Catherine, Duchess of Cambridge, is all smiles the day before the opening ceremonies of the 2012 Olympics. AFP/Chris Jackson

Britain's Catherine (R), Duchess of Cambridge chats with Prince William, standing next to Prince Harry (L), during a visit to Bacon's college to launch the Coach core sports program, which is a partnership between the Royal Foundation of The Duke and Duchess of Cambridge and Greenhouse charity, a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Richard Pohle/Pool

Britain's Catherine, Duchess of Cambridge plays table tennis a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Chris Jackson/Pool

The shoes of Catherine, Duchess of Cambridge are seen as she leaves after a torch relay at the Buckingham Palace in London, on July 26, 2012 on the eve of the London 2012 Olympic Games. AFP/ARTHUR EDWARDS

Prince William, Catherine and Prince Harry wait for the arrival of the Olympic Flame before a torch relay at the Buckingham Palace in London, on July 26, 2012 on the eve of the London 2012 Olympic Games. AFP/IAN WEST

Britain's Catherine, Duchess of Cambridge, is seen with Prince Harry the day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Richard Pohle/Pool

Britain's Catherine, Duchess of Cambridge plays table tennis a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Chris Jackson/Pool

Britain's Prince William, along with Catherine, Duchess of Cambridge and Prince Harry watch as Olympic torch bearer Wai-Ming Lee hands over the flame to John Hulse (R) during a visit to Buckingham Palace in London July 26, 2012. REUTERS/Ian West/Pool

Catherine, Duchess of Cambridge plays table tennis the day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Pool

Britain's Catherine (R), Duchess of Cambridge looks on as Prince William holds a ball during a visit to Bacon's college to launch the Coach core sports program a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Richard Pohle/Pool

Prince William, his wife Catherine, and Prince Harry applaud to welcome a torchbearer holding the Olympic Flame at Buckingham Palace in London, on July 26, 2012 on the eve of the London 2012 Olympic Games. AFP/ARTHUR EDWARDS

Britain's Catherine, Duchess of Cambridge judges a judo match a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Chris Jackson/Pool

Catherine, Duchess of Cambridge, and Prince Harry wait for the arrival of the Olympic Flame before a torch relay at the Buckingham Palace in London, on July 26, 2012 on the eve of the London 2012 Olympic Games. AFP/ARTHUR EDWARDS

Britain's Prince Harry and Catherine, Duchess of Cambridge look on as they wait for Olympic torch bearer Wai-Ming Lee to hand over the flame to John Hulse at Buckingham Palace in London July 26, 2012. REUTERS/Ian West/Pool

The bare feet of Britain's Catherine, Duchess of Cambridge are seen during a visit to Bacon's college to launch the Coach core sports programm a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Chris Jackson/Pool

Britain's Catherine, Duchess of Cambridge plays table tennis a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Chris Jackson/Pool

Prince William (L), Duke of Cambridge and Catherine (2dL), Duchess of Cambridge stand next to Prince Harry (R) as torchbearer John Hulse (R) holds the Olympic Flame after a torch relay at the Buckingham Palace in London, on July 26, 2012 on the eve of the London 2012 Olympic Games. AFP/IAN WEST

Prince William (2dL), Duke of Cambridge and Catherine (3dL), Duchess of Cambridge stand next to Prince Harry (2dR) during a torch relay from Wai-Ming (L) to John Hulse (R) at the Buckingham Palace in London, on July 26, 2012 during a torch relay on the eve of the London 2012 Olympic Games. AFP/IAN WEST

Britain's Catherine, Duchess of Cambridge, plays table tennis a day before the London 2012 Olympics opening ceremony in Rotherhithe, London July 26, 2012. REUTERS/Chris Jackson/Pool

Prince William, Duke of Cambridge, his wife Catherine, Duchess of Cambridge, and Prince Harry welcome a torchbearer holding the Olympic Flame at Buckingham Palace in London, on July 26, 2012. AFP/ARTHUR EDWARDS