The Duke and Duchess of Cambridge are expecting a baby, St James's Palace announced today.
The Queen and Duke of Edinburgh, the Prince of Wales and members of both families are delighted with the news, said a spokesman.
But St James's Palace said in a statement that Kate had been admitted to a private hospital for treatment for a severe form of morning sickness known as hyperemesis gravidarum.
St James's Palace said in the statement: ''The Duchess was admitted this afternoon to King Edward VII Hospital in central London with hyperemesis gravidarum.
''As the pregnancy is in its very early stages, Her Royal Highness is expected to stay in hospital for several days and will require a period of rest thereafter."
The palace said the duchess was admitted this afternoon to the King Edward VII Hospital in central London with acute morning sickness and is expected to stay in hospital for several days.
Prime Minister David Cameron wrote on Twitter that he was ''delighted by the news'', adding: ''They will make wonderful parents.''