Prince William and Kate Middleton officially announce third royal baby's due date

Prince William and Duchess Catherine are expecting their third child in April 2018.

The British royal couple - who are already parents to Prince George, four, and Princess Charlotte, two - have confirmed 35-year-old Catherine's due date following them announcing that she was pregnant again in September.

A statement issued by Kensington Palace said: "The Duke and Duchess of Cambridge are delighted to confirm they are expecting a baby in April 2018."

The new baby will be the fifth in line to the throne, with Prince Harry - the child's uncle - being pushed into sixth.

William, 35, and Catherine - previously known as Kate Middleton - will kick off an exciting year with an official royal tour of Norway and Sweden in early 2018.

Kensington Palace announced: "The Duke and Duchess of Cambridge will undertake an official visit to Norway and Sweden at the request of the FCO in early 2018."

Photo / Getty

Although Duchess Catherine has once again been suffering from hyperemesis gravidarum - a severe form of morning sickness - she still made a public appearance as she danced with Paddington Bear at Paddington Station for a charity event.

After Catherine busted some moves, the couple and Prince Harry, 33, boarded a train where they met with children who are involved with the charities they support, as well as their families.

- Bang! Showbiz