LONDON – The Duchess of Cambridge, granddaughter-in-law to the Queen of England and wife of Prince William, is pregnant with her third child, Kensington Palace – the couple’s official residence – said on Monday.

The Dukes of Cambridge are parents to two children: Prince George, 4, and Princess Charlotte, 2.

“The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge is expecting their third child,” a palace statement said.

“The Queen and members of both families are delighted with the news,” it added.

Prince William, the Duke of Cambridge, who is second in the line of succession to the British crown, married Catherine Middleton in April 2011 at a glittering ceremony held in Westminster Abbey, the church where kings of England have traditionally been crowned.

As in her previous pregnancies, the 35-year-old duchess has suffered from a severe form of morning sickness called hyperemesis gravidarum, which forced her to cancel a charity event scheduled for Monday, the statement said.

The duchess, who was scheduled to visit a children’s center in north London, will instead be treated for nausea at Kensington Palace, the statement added.

News of the pregnancy came a few days after the 20th anniversary of the death of Diana of Wales, the Duke of Cambridge’s mother, who died in a car crash in Paris on Aug. 31, 1997.

Also, the announcement came days before Prince George, third in the line of succession to the British throne, is due to begin his first day of school in London.