The one royal rule that Prince William and Kate Middleton always break

They're one of the most adorable families out - and while we already can't get enough of them, our admiration has just grown even more...

We all know when it comes to the royal family, there are many rules they have to strictly follow; be it the one food they're not allowed to order at a restaurant or the extra outfit they have to pack when travelling.

But when it comes to their children, Princess Kate and Prince William don't always abide by the rules.

The proud parents are often joined by their little ones on royal engagements. Every time they arrive in a new country, the family arrives together.

But there's actually a royal protocol - put in place as a safety measure - that more than one heir is not allowed to travel together, in case of a crash.

The 40-year-old dad first rebelled against the rules a year after his eldest son Prince George was born, when the then family of three came to New Zealand.

At the time, the future king had to ask Queen Elizabeth II for special permission to fly with baby George on board.

Considering William, George, Charlotte and Louis are all heirs to the throne, the family should never travel together.

We love how hands-on the Prince and Princess of Wales are!