Prince William Shares the Hysterical ‘Knock Knock Joke’ Princess Charlotte Is Telling Everyone

Prince William is revealing what always makes his daughter Princess Charlotte laugh.

On April 25, William made a solo trip to the West Midlands. His first since Princess Catherine revealed she is battling cancer.

The prince met with several students from the St. Michael’s Church of England High School. There he talked about the importance of mental health.

While talking with the students, he was asked to lighten the mood with a “dad joke.” And Prince William pulled inspiration from his daughter, Charlotte, Entertainment Tonight reports.

“I think what I’ll do is I’m going to say a joke that is Charlotte’s favorite joke at the moment that she keeps telling me,” he told the students. “You’re going to have to interact with me. It’s not a joke I can say straight away.”

“Knock, Knock,” the prince said. “Who’s there,” they responded. “Interrupting cow,” the prince added.

But before the students could answer with the traditional, “Interrupting cow who?” The prince quickly interjected with a quick, “Moo!”

“That’s one I hear a lot at the moment,” Prince William said with a chuckle. “That the greatest one I can think of at the moments that’s clean and broadcast-able.”

The joke was met with laughter from the audience. “I was kind of trying to channel Jack Whitehall because most of his jokes are pretty dad-like,” he claimed.

“It’s good,” one of the students said.