Britain’s Prince William and his wife Kate are expecting their third child, the Kensington Palace announced on Monday.

The Duke and Duchess of Cambridge, have two children — Prince George and Princess Charlotte — aged four and two.

“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.

Ms. Kate is suffering from Hyperemesis Gravidarum, a form of severe morning sickness, and will not carry out her engagements on Monday, it said. The Queen and both families are said to be “delighted with the news”.