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. Photographer Ian Gavan - WPA Pool supplied by Ian Jones Photography.

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. Photographer Ian Gavan - WPA Pool supplied by Ian Jones Photography.

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. Photographer Ian Gavan - WPA Pool supplied by Ian Jones Photography.

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. Photographer Ian Gavan - WPA Pool supplied by Ian Jones Photography.

Catherine, Duchess of Cambridge arrives ahead of the British Royal family Christmas Day church service at St Mary Magdalene Church in Sandringham, Norfolk, in the east of England, on December 25, 2011. AFP PHOTO/BEN STANSALL

Catherine, the Duchess of Cambridge, arrives to attend the Royal family Christmas Day church service at St Mary Magdalene Church in Sandringham, Norfolk, eastern England, on December 25, 2011. Britain's Prince Philip missed the royal family's Christmas Day celebrations for the first time as the husband of Queen Elizabeth II remained in hospital after having heart surgery. AFP PHOTO / BEN STANSALL

Catherine, Britain's Duchess of Cambridge, arrives at Centrepoint's Camberwell Foyer in London, on December 21, 2011. The national charity, Centrepoint, provides housing and support to improve the lives of homeless young people aged 16-25. AFP PHOTO/CARL COURT

Britain's Prince William, Duke of Cambridge (L), and his wife Catherine, Duchess of Cambridge (R), attend a reception during a visit to Centrepoint's Camberwell Foyer in London on December 21, 2011. The national charity, Centrepoint, provides housing and support to improve the lives of homeless young people aged 16-25. AFP PHOTO / POOL / BEN STANSALL

Catherine, Britain's Duchess of Cambridge, watches a performance during a visit to Centrepoint's Camberwell Foyer in London on December 21, 2011. The national charity, Centrepoint, provides housing and support to improve the lives of homeless young people aged 16-25. AFP PHOTO / POOL / BEN STANSALL

Catherine, Britain's Duchess of Cambridge, applauds following a performance during a visit to Centrepoint's Camberwell Foyer in London on December 21, 2011. The national charity, Centrepoint, provides housing and support to improve the lives of homeless young people aged 16-25. AFP PHOTO / POOL / BEN STANSALL

LONDON-ENGLAND-13-NOV-2011: The traditional Remembrance Sunday Service at the Cenotaph in London attended by members of the British Royal Family led by HM Queen Elizabeth and HRH The Duke of Edinburgh. Also in attendance were Prince Charles, Duke of York, Prince Edward and Prince William. Camilla, HRH The Duchess of Cornwall, Catherine The Duchess of Cambridge and The Countess of Wessex watched from a balcony. Wreaths were laid on the memorial to those who lost their lives in conflict. Pic shows Catherine, HRH The Duchess of Cambridge, KATE.

Britain's Prince William (L) and Catherine, Duchess of Cambridge (R) arrive to attend a dinner reception in aid of the National Memorial Arboretum Appeal at St James's Palace, in London, on November 10, 2011. The Appeal was launched in April 2009 by its Patron, The Duke of Cambridge, to develop the Arboretum into a world-renowned centre for Remembrance and to ensure that there are necessary facilities for the 300,000 visiting families, servicemen and women, veterans and members of the public each year. AFP PHOTO/WPA POOL/ LEFTERIS PITARAKIS

Catherine, the Duchess of Cambridge, arrives for a visit of UNICEF's global Supply Centre in Copenhagen, on November 2, 2011. AFP PHOTO/JONATHAN NACKSTRAND

COPENHAGEN, DENMARK- 2 NOV-2011: Prince William and Catherine, The Duke and Duchess of Cambridge visit UNICEF's emergency supply centre in Copenhagen accompanied by The Crown Prince and Crown Princess of Denmark. William and Kate tour the supply division with Prince Frederik and Princess Mary packing boxes and viewing displays of emergency equipment. Pool photo supplied by Ian Jones

COPENHAGEN, DENMARK- 2 NOV-2011: Prince William and Catherine, The Duke and Duchess of Cambridge visit UNICEF's emergency supply centre in Copenhagen accompanied by The Crown Prince and Crown Princess of Denmark. William and Kate tour the supply division with Prince Frederik and Princess Mary packing boxes and viewing displays of emergency equipment. Pool photo supplied by Ian Jones

LONDON, ENGLAND- 26-10-11-ROTA- A St James's Palace handout photograph of Prince William and Catherine, the Duke and Duchess of Cambridge to coincide with their visit to Copenhagen EDITORIAL USE ONLY Photographer Chris Jackson, Handout Pool Photo supplied by ian Jones Photography

Britain's Prince William and Catherine, the Duke and Duchess of Cambridge attend a Charity Gala Evening hosted by 100 Women in Hedge Funds at St James's Palace. Prince William is Patron of the fundraising City organisation which has raised more than L675,000 for the Child Bereavement Charity, another of William's Charities. Kate wore a full lenght red dress by Belulah, London Photograph by Theo Wood, supplied by Ian Jones Photography.

Britain's Prince William and Catherine, the Duke and Duchess of Cambridge attend a Charity Gala Evening hosted by 100 Women in Hedge Funds at St James's Palace. Prince William is Patron of the fundraising City organisation which has raised more than L675,000 for the Child Bereavement Charity, another of William's Charities. Kate wore a full lenght red dress by Belulah, London Photograph by Theo Wood, supplied by Ian Jones Photography.

Britain's Prince William and Catherine, the Duke and Duchess of Cambridge attend a Charity Gala Evening hosted by 100 Women in Hedge Funds at St James's Palace. Prince William is Patron of the fundraising City organisation which has raised more than L675,000 for the Child Bereavement Charity, another of William's Charities. Kate wore a full lenght red dress by Belulah, London Photograph by Theo Wood, supplied by Ian Jones Photography.

Britain's Prince William and Catherine, the Duke and Duchess of Cambridge attend a Charity Gala Evening hosted by 100 Women in Hedge Funds at St James's Palace. Prince William is Patron of the fundraising City organisation which has raised more than L675,000 for the Child Bereavement Charity, another of William's Charities. Kate wore a full lenght red dress by Belulah, London Photograph by Theo Wood, supplied by Ian Jones Photography.