THE Duke and Duchess of Cambridge have confirmed they are expecting a baby.

St James’s Palace made the announcement on the couple’s behalf after Kate was admitted to hospital this afternoon.

She was taken by car to the King Edward VII Hospital in central London with acute morning sickness and is expected to stay in hospital for several days.

In a statement St James’s Palace said: “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.”

St James’s Palace also confirmed that William is by his wife’s side in hospital.

The spokesman, who said the Queen and members of both families are delighted with the news, would not say when the royal couple became aware of the pregnancy, only saying “recently”.

It is understood that the pregnancy has not passed the 12-week stage and that the announcement was prompted by the Duchess’s medical condition.

William’s uncle Earl Spencer welcomed the announcement. He said: “It is wonderful news and I am thrilled for them both.”

The baby would have been a first grandchild for William’s late mother and the Earl’s sister, Diana, Princess of Wales.

Kate’s last public engagement was at her former prep school, St Andrew’s in Pangbourne, Berkshire, where she showed off her hockey skills.

A spokeswoman said they had “no inkling at all” that she was expecting.

“Obviously everyone at St Andrew’s are delighted for them both. We’re absolutely thrilled,” she added.

Messages of congratulations on Twitter have come from Prime Minister David Cameron who said he was “delighted by the news” and added: “They will make wonderful parents.”

While Labour leader Ed Miliband said: “Fantastic news for Kate, William and the country. A royal baby is something the whole nation will celebrate.”

The couple have been congratulated by the Royal Air Force, with which William serves as a search-and-rescue pilot, and the University of St Andrew’s, where William and Kate met.

The Duchess had a number of engagements this week but they have all been cancelled, St James’s Palace confirmed.