Kensington Palace announced on Monday, that Prince Wiiliam and Kate are expecting a third child, as she was forced to cancel a public event due to acute morning sickness.
The 35-year-old is suffering from hyperemesis gravidarum, a condition that plagued her two previous pregnancies, and is being treated at home.
She has not yet reached the 12-week stage when women normally make the news public but made the announcement after being unable to attend an event in London on Monday afternoon, a spokeswoman said.
William is second in line to the throne and the new baby will be fifth in line, pushing William’s younger brother Harry down the order of succession.
“Their royal highnesses the Duke and Duchess of Cambridge are very pleased to announce that the Duchess of Cambridge is expecting their third child,” the palace said in a statement.
Queen Elizabeth II, William’s grandmother, and his father Prince Charles were said to be “delighted” at the news, while Harry said he was “very, very happy for them”.
The news comes as William and Kate’s eldest child, four-year-old Prince George, who is third in line to the throne, prepares to start school in London on Thursday.
The couple also have a daughter, two-year-old Princess Charlotte.
The palace declined to say when the new baby was due, but a spokeswoman confirmed to AFP that Kate “hasn’t reached the 12-week stage yet”.
Many women wait until they are 12 weeks pregnant to announce the news, due to the risk of miscarriage.
“As with her previous two pregnancies, the Duchess is suffering from hyperemesis gravidarum,” the official palace statement said.
“Her royal highness will no longer carry out her planned engagement at the Hornsey Road Children’s Centre in London today. The Duchess is being cared for at Kensington Palace.”
Kate was only around a month pregnant with Charlotte when the news was announced, again because she had to cancel a public engagement.