Britain's Kate and Prince William expecting a baby

LONDON: Britain's Prince William and his wife Catherine are expecting a baby, destined to be the country's future monarch, although the mother-to-be is in hospital with a type of very acute morning sickness that sometimes indicates twins.

"Their Royal Highnesses The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge is expecting a baby," the prince's office said in a statement on Monday, adding that Queen Elizabeth and the royal family were delighted.

A spokeswoman for the couple said 30-year-old Catherine, widely known as Kate, was in the King Edward VII Hospital in central London suffering from Hyperemesis Gravidarum, an acute morning sickness which causes severe nausea and vomiting and requires supplementary hydration and nutrients.

Draycott told Reuters it may also indicate more than one royal baby may be in the offing.

"Hyperemesis is slightly more common with twins," said Draycott.

William, a Royal Air Force helicopter pilot, was at her side and she is likely to remain in hospital for several days.

"I'm delighted by the news that the Duke and Duchess of Cambridge are expecting a baby," Prime Minister David Cameron said on his Twitter website. "They will make wonderful parents."