It is said the royal, who will marry Meghan Markle, 36, on 19 May this year, played a practical joke on the wedding organisers on the special day.
An upcoming documentary on royal weddings will tell the story of how Prince Harry caused a stir on the day.
It is known Kate and William had two wedding cakes on the special day: one fruit cake and one chocolate tiffin cake. Harry played a joke with the latter.
Master chocolatier Barry Colenso, who created Prince William and Kate Middleton’s second chocolate tiffin cake, explained what happened.
He recounted: “We’d just finished the cake, and I remember Harry came bounding in.
“Then he pretended to box with the top decoration. We were all like: “Oh no!”.
Later in the programme, the chocolatier describes the measures he went to to take care of the cake on the wedding day.
He said: “We made two full cakes and we knew we had to drive it to Buckingham Palace.
“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 programme, Invitation To A Royal Wedding, will air on Sunday 29th April at 9pm on ITV.
Some of Prince Harry and Meghan Markle’s royal wedding plans were revealed earlier today.
Meghan Markle and Prince Harry’s wedding celebrations will end in an after party including a disco and late night food, Express.co.uk can exclusively reveal.
It will include some unexpected twists inspired by the wedding of Kate Middleton and Prince William in 2011.
Firstly, the party will include a disco which takes place at Meghan and Prince Harry’s first choice of wedding venue.
“Prince Harry is planning to use Frogmore House for a disco,” a palace source revealed.
It has also been revealed that the pair will serve late night food for guests towards the end of the party.
“Prince Harry is planning to use ice cream vans the same way Kate and William did,” said the source.