LONDON — The most widely anticipated pregnancy since Princess Diana's in 1981 is official: Prince William's wife, Kate, is pregnant.
St. James's Palace announced the pregnancy Monday, saying that the Duchess of Cambridge — formerly known as Kate Middleton — has a severe form of morning sickness and is currently in a London hospital. William is at his wife's side.
News of the pregnancy drew congratulations from across the world, with the hashtag "royalbaby" trending globally on Twitter.
The couple's first child will be third in line to take the throne — leapfrogging the gregarious Prince Harry and possibly setting up the first scenario in which a U.K. female heir could benefit from new gender rules about succession.
The palace would not say how far along the 30-year-old duchess is, only that she has not yet reached the 12-week mark. Palace officials said the duchess was hospitalized with hyperemesis gravidarum, a potentially dangerous type of morning sickness where vomiting is so severe no food or liquid can be kept down. They said she was expected to remain hospitalized for several days and would require a period of rest afterward.
"The best advice for anyone suffering from (severe morning sickness) is to get plenty of rest and drink lots of fluid," Dr. Daghni Rajasingam, a spokeswoman for Britain's Royal College of Obstetricians and Gynaecologists, said in a statement. "The condition usually subsides by week 12 of the pregnancy and with early diagnosis and treatment, there is no reason why we shouldn't expect a healthy pregnancy."
The condition is thought to affect about one in 200 pregnant women, according to Britain's health department.
The news came just days after the duchess, on a royal appearance, played field hockey with children at her former school.
Not only are the attractive young couple popular — with William's easy common touch reminding many of his mother, the late Diana — but their child is expected to play an important role in British national life for decades to come.