Prince Harry
Prince Harry played a practical joke during Prince William and Kate Middleton's royal wedding. Pictured: Prince William, Middleton, Prince Harry and Pippa Middleton as they walk down the aisle inside Westminster Abbey on April 29, 2011 in London. Getty Images/Kirsty Wigglesworth

Prince Harry caused a stir during Prince William and Kate Middleton's royal wedding in 2011.

A new ITV documentary clip revealed that Prince Harry played a shocking joke during his brother's nuptials. The Duke and Duchess of Cambridge had two wedding cakes - a fruitcake and a chocolate tiffin cake. The ginger redhead royal reportedly played with the latter.

"We'd just finished the cake, and I remember Harry came bounding in," master chocolate Barry Colenso said (via Express). "Then he pretended to box with the top decoration. We were all like: 'Oh no!'"

Fortunately, it was just a joke. Later in the programme, Colenso shared the measures he took to deliver the cake without problems.

"We made two full cakes and we knew we had to drive it to Buckingham Palace," the chocolatier added. "So we organised two vehicles that would go separately. What happens if one of them was in an accident? They were carrying precious cargo. I took one of the vans and drove the route three times, literally noting every pothole, every corner."

The "Invitation To A Royal Wedding" documentary will air on April 29 at 9 p.m. on ITV.

In related news, Prince Harry chose his older brother, Prince William, to be his best man. When the Duke married Middleton seven years ago, Markle's fiance also served as the best man.

"Revenge is sweet. I'll be looking forward to it," Prince William said on being selected as Prince Harry's best man.

When the groom-to-be was asked how he requested his older brother to play the same role at his wedding, he joked, "went down on one knee." "He's known for ages," Prince Harry added.

Aside from Prince William, Prince George and Princess Charlotte are expected to be part of the royal wedding's entourage as a page boy and bridesmaid or flower girl. In fact, a royal expert confessed that she would be shocked if she would not see the two little royals on their uncle Harry's big day.

"George and Charlotte are Harry's only niece and nephew, so it would be a real shocker if they were not included," Marlene Koenig told Harper's Bazaar. "In Britain, the bride goes down the aisle first, followed by attendants or bridesmaids and page boys holding the train."

Prince Harry and Markle are tying the knot on May 19 at St. George's Chapel at Windsor Castle.