Prince William’s wife Catherine is expecting a baby and is in hospital suffering severe morning sickness, St James’s Palace announced on Monday.
The royal family are “delighted” by the news of the baby, who would be the third in line to the British throne currently occupied by Queen Elizabeth II.
“Their Royal Highnesses The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge is expecting a baby,” St James’s Palace said in a statement.
“The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall and Prince Harry and members of both families are delighted with the news.”
William, the son of heir to the throne Prince Charles and the late Princess Diana, married the former Kate Middleton in April 2011 and there has been intense speculation about when the couple, who are both 30, would have a baby.
The statement added: “The Duchess was admitted this afternoon to King Edward VII Hospital in Central London with Hyperemesis Gravidarum (severe morning sickness).
“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.”
British Prime Minister David Cameron said the royal couple would make “wonderful parents”.
“I’m delighted by the news that the Duke and Duchess of Cambridge are expecting a baby,” he wrote on his Twitter account. “They will make wonderful parents.”
Speculation about a royal pregnancy intensified last week following an incident when the couple visited Cambridge, the historic English university city which is home to their dukedom.
William laughed and said “I’ll keep that” when he was given a home-made baby romper suit on Wednesday as they made their first visit as a couple to the city.
Samantha Hill, 27, hand-stitched the tiny outfit with the words “Daddy’s little co-pilot”, a reference to William’s job as a search and rescue helicopter pilot with the Royal Air Force.
“I made it for when his little one comes along,” said Hill, whose own daughter Beth is just four weeks old. “He’s a helicopter pilot so his baby will think his daddy is cool.”
The baby news comes just over one year since Commonwealth nations agreed to scrap centuries-old laws barring first-born daughters from inheriting the British throne.
The laws also barred anyone married to a Roman Catholic from inheriting the throne.
The 1701 Act of Settlement had formalised the policy of male primogeniture, although the tradition dates back even further to feudal times and beyond.
Under the law, female heirs to the throne had been passed over if younger male heirs are available.
Queen Elizabeth II was crowned in 1953 only because she did not have any brothers.
The queen already has two great-grandchildren through her eldest grandchild Peter Phillips, the son of her daughter Princess Anne.