Prince William and Duchess Kate often take their children Prince George, Princess Charlotte and Prince Louis with them on engagements and trips abroad.

But Prince George in particular tends to stand out with one choice of clothing. Regardless of the weather or the occasion, the 7-year-old always wears shorts, which are often combined with knee socks.

Why Prince George always wears shorts

Despite what you might think, the unusual style isn't a choice of the young royal himself or his mother Duchess Kate. On the contrary, it's almost a sort of dress code that Prince George must follow.

Princess Charlotte, Duchess Kate, Prince George, Prince William

Ingrid Seward, the royal expert and editor-in-chief of Majesty, is very familiar with the customs of the British Royal Family. This was her explanation of the shorts tradition:

"Boys wear short trousers until they are 8. It is very English," Seward told People magazine after a controversy when young Prince George wore shorts in cold weather.

Long pants are taboo for young British royals

So, long trousers are a little "taboo" for young British royals. It will be another month still before George is allowed to wear long pants in public. He turns 8 in July.

But it will also be a special moment when he no longer has to wear shorts. Of the milestone, Seward said: "[The boys] suddenly feel very grown up."

There are a few exceptions, by the way. Prince George wore long pants as a page boy at the weddings of Prince Harry and Duchess Meghan and Princess Eugenie and her husband.

Even when he visited the theatre, Prince George was allowed to wear a different outfit than usual. The tradition has already been relaxed since with his brother Louis — he was allowed to wear long trousers from a young age.

Otherwise, Prince George has been carrying on a tradition followed also by his father Prince William and his father Prince Charles, the trio representing the next three in line to the British throne.