The Duke and Duchess of Cambridge are expecting their first child, St James's Palace has officially confirmed.

"Their Royal Highnesses The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge is expecting a baby," their official statement said.

"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. 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. Hyperemesis Gravidarum is very acute morning sickness, which requires supplementary hydration and nutrients".

Dr. Kecia Gaither, director of maternal fetal medicine at Brookdale University and Medical Center in New York, said that the Duchess would likely be back to her usual life in a few days.

"She should be able to meet all her public obligations soon," she said. "She should just be looking forward to having a healthy little plump person."

According to Us Weekly, Prince William and his wife will move to a more "secure environment" in preparation for the baby. The two will reportedly make their permanent home in Apartment 1A of London's Kensington Palace, a four-storey, 20-room flat currently undergoing a £932082 ($1.5 million) renovation.

"Kate is keen to put her stamp on the place with things she's bought on her travels," a source told Us Weekly, "She felt certain pieces would be nice 'when we have a bigger home.'"

The Duke of Cambridge also recently accepted a babygro from a member of the public on a royal visit to Cambridge.

Meanwhile, the Duchess's friend, Jessica Hay, had hinted that the couple would be announcing the pregnancy in December.

The 30-year-old mother-to-be was recently spotted during a visit to Saint Andrew's school in southern England, which she attended from 1986 to 1995, to open a new hockey pitch. She was quick to take to the hockey field, joining a group of 12-year-olds for a training game in knee-high, heeled boots.

Take a look at the royal parents-to-be...