The Duchess of Cambridge's uncle thinks she and Prince William will have more than three children.

The Cambridge's

The Cambridge's

Gary Goldsmith was overjoyed to hear that his niece - who already has Prince George, four, and two-year-old Princess Charlotte with William - is set to become a mother for the third time and has predicted they will continue to add to their family.

The wealthy business owner told the MailOnline: "It's the best news I've had so far this year.

"She's a natural mother.

"I wonder if she will stop at three? I doubt it. They are having such fun with the babies."

The British royal couple announced their baby news to the world on Monday morning (04.09.17).

Kensington Palace said in a statement: "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 Queen and both their families are delighted with the news."

Unfortunately for Catherine she is once again suffering from Hyperemesis Gravidarum - a debilitating form of serious morning sickness - and was forced to cancel a planned official engagement in London later in the day.

The statement concluded: "As with her previous two pregnancies, the Duchess is suffering from Hyperemisis Gravidarum. 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."

William's younger brother Prince Harry was one of the first to congratulate the couple on their baby news.

The 32-year-old royal was meeting with victims of the Manchester terrorist attack - which saw a bomb detonated at an Ariana Grande concert in May - when he was asked about the news.

He told reporters: "[It's] fantastic, great. Very, very happy for them."

And he also reassured well-wishers that Catherine is doing "OK" despite being poorly.

He said: "I haven't seen her for a while but I think I she's OK."

The arrival of the royal baby will see Harry bumped to sixth in line to the throne, behind his father Prince Charles, brother William and his sibling's brood.