The Duke of Cambridge thinks his daughter will be "trouble" when she grows up, although Prince George currently "rules the roost".
The 35-year-old royal has admitted his oldest child Prince George, four, - who he has with his wife the Duchess of Cambridge - currently "rules the roost", but he has revealed his youngest offspring, Princess Charlotte, two, is not far behind and he has no doubts she will cause mayhem as she grows up.
Speaking about his brood to a patient named Pagan Tordengrav during his visit to Aintree University Hospital, in Liverpool, on Thursday, which has also been reported on PEOPLE, Prince William said: "George rules the roost but Charlotte isn't far behind. I think she's going to be trouble when she's older."
William has revealed he has even been warned by fellow fathers how to handle his daughter.
He said: "All fathers say that to me - watch out for the little girls."
And it won't be long until William and Duchess Catherine - who was formerly known as Kate Middleton prior to marrying the royal - welcome a third child into their family, as the couple recently announced they are expecting another baby together.
The couple - who got married in 2011 - previously released a statement to announce the news, which read: "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 members of both families are delighted with the news.
"As with her previous two pregnancies, The Duchess is suffering from Hyperemesis 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."