Prince William Told Princess Charlotte's Favorite Joke, And I'm Cackling

Prince William has shown off his daughter Princess Charlotte's hilarious sense of humor during a recent royal visit.

The Prince of Wales was visiting St. Michael's Church of England High School in Rowley Regis, in England's West Midlands, when he was asked to tell a "dad joke."

Thankfully, the prince was prepared because Charlotte, who turns 9 next week, has a favorite joke at the moment—and it felt pretty appropriate in a school visit context.

"I think what I'll do is I'll tell a joke that is Charlotte's favorite at the moment—she keeps saying it," he said. "I'll do that instead. But you're gonna have to interact with me, it's not a joke I can tell straightaway."

William began, "Knock knock," with the kids, answering, "Who's there?" He then told them, "Interrupting cow." The students went to ask, "Interrupting cow who?" but before they could finish asking the question, William said, "Moooo!"

The kids giggled, and the royal added, "That's the greatest one I could think of. It's clean, and broadcastable."

William was at the school after a boy named Freddie Hadley (sat next to him while he was telling the joke) invited him to an event for male mental health last fall, and asked him if he could support their #AmIManlyEnough campaign.

After his school shared the invitation on Twitter, William answered, "Good afternoon Freddie, I’m so sorry Catherine and I can’t be with you and the rest of the students at St Michael’s today. Tackling mental health challenges and stigmas head on is so important, please keep up this important work. W"

That clearly got William's attention at the time, since he then went on to visit the school and chat about boys' mental health with Freddie and other members of the Matrix Project.