Prince Harry shocked his father, Prince Charles, during his 50th birthday celebration.

The Duke of Sussex and Prince William agreed to surprise their dad at the bash. But Prince Harry decided to do so much more.

In the book “Harry: Conversations With the Prince,” royal author Angela Levin revealed how Prince William and Prince Harry staged a full Monty-style strip. At that time, Prince Harry was just 14 years old, but he reportedly got very drunk at his dad’s party.

The agreement was for him and Prince William to take off a few items of clothing, but Prince Harry ended up getting completely naked. And to make things worse, he even ran around the venue without his clothes on and left Prince Charles shocked.

“In fact, he turned crimson, but he told a group of us later that it was just teenage high spirits and he himself had done much the same. It was the only time in my life that I didn’t believe him,” Levin said.

But Prince Harry never really shied away from admitting that he was very naughty especially while he was growing up. In fact, he previously told the royal author that he deliberately chose to be a “bad boy” while studying at Eton. And while he was there, he was best known for his naughty streak.

Meghan Markle’s husband revealed that Princess Diana taught him an important lesson about being naughty. The late royal said that it’s fine to be naughty as long as he doesn’t get caught. The Princess of Wales wasn’t one to reprimand her youngest son for his bad behavior because she herself also admitted that Prince Harry’s naughtiness came from her.

And just like Princess Diana, Prince Harry also enjoyed playing pranks on his family and friends.

“Once he balanced a book above a door so that it fell on the teacher’s head when he entered the classroom and made his brother jump by leaping out from behind a tree during a cross-country race,” Levin said.