"And children are really fascinated by faces, and your faces are all over your cooking books and he would say, 'That's Mary Berry'. So he would definitely recognise you if he saw you."
The Duke and Duchess are also both fans of Mary, who is best known for starring on 'The Great British Bake Off'.
Meanwhile, it was recently revealed that the Duke encourages his children to treat each other equally.
The 37-year-old royal - who also has Prince George, six, and Princess Charlotte, four, with his wife - likes to ensure his kids play fair when they take part in games.
Speaking about the Duke's approach to parenting, Olivia Hancock - who promotes gender equality in sport - explained: "He said, 'When George and Charlotte play football, George gets Charlotte to go in goal because he says he is better.'
But Prince William says to him, 'Charlotte could be as good as you, George, so give her the same chances.'
"I think that was really good as it shows Prince William is standing up for equality as well. He is doing something for women in sport."
