Kate Middleton and Prince William are expecting their third child together, it has been announced.

Kensington Palace tweeted on Monday morning that the royal couple are "very pleased to announce" that Middleton is expecting their third baby.

It has not yet been revealed when Middleton is due to give birth.

The Duke and Duchess of Cambridge are already parents to 4-year-old Prince George and 2-year-old Princess Charlotte.

Their third child would be fifth in line to the British throne, bumping Prince Harry down to sixth place.

Prince William and Kate Middleton with their son Prince George and daughter Princess Charlotte

A further press release from Kensington Palace said that the Queen and members from both families are "delighted" with the news.

The statement added that as with her previous two pregnancies, Middleton is suffering from acute morning sickness, known as Hyperemesis gravidarum, and was unable to carry out an official engagement planned for London on Monday. She is currently being cared for at Kensington Palace.