In an upcoming television special called "A Berry Royal Christmas," the Duchess of Cambridge, 37, revealed to professional baker and "The Great British Bake Off" judge Mary Berry that Louis frequently would say "Mary" while watching the show, the BBC reported.
"One of Louis' first words was Mary, because right at his height are all my cooking books in the kitchen bookshelf. And children are really fascinated by faces, and your faces are all over your cooking books and he would say 'That's Mary Berry,'" Kate said.
She added: "He would definitely recognize you if he saw you today."
Berry, 84, has served as a judge on the show, in which contestants face a series of baking challenges.
The BBC specia is to feature Berry assisting Kate and her husband, Prince William, in preparing food to thank those who have volunteered with them throughout the year.
Louis, 1, and his siblings George, 6, and Charlotte, 4, are not set to appear in the special.