Prince William is rarely seen wearing tracksuits and jeans when he is out in public.

During most occasions, the future king always wears chinos of slacks, and there’s a reason why this is the case. Former royal butler Grant Harrold previously told BBC that majority of the places that Prince William visit do not allow jeans because they are still seen as casual wear.

“So, it is better to play safe for both sexes. But if the Duke is outside walking the dogs for example, then jeans are fine,” he said.

Prince William’s eldest child, Prince George, doesn’t also wear trousers in public. Etiquette expert William Hanson told Harper’s Bazaar last year that it is a very English thing to dress a young boy in shorts.

“Trousers are for older boys and men, whereas shorts on young boys is one of those silent class markers that we have in England. Although times are slowly changing, a pair of trousers on a young boy is considered quite middle class – quite suburban… And no self-disrespecting aristo or royal would want to be considered suburban, even the Duchess of Cambridge,” he said.

Hanson went on to say that young boys usually graduate from wearing shorts to trousers at around 8 years old. This is potentially due to the practice of breeching, which dates back to the 16th century.

The etiquette expert that a newborn boy is usually dressed in a gown for the first two years and then he is breeched and starts wearing articles of clothing that resembled shorts or trousers than dresses.

Meanwhile, Princess Charlotte has only been seen in a dress in public. The 4-year-old daughter of Prince William and Middleton has never been photographed in pants or leggings.

Children’s wear designer Rachel Riley told Harper’s Bazaar that Princess Charlotte is always in a dress to avoid looking out of date.

Prince William
Prince William attends the unveiling of The Victoria Cross Commemorative Paving Stones representing each of Birmingham's 1st World War recepients at the Hall of Memory, Centenary Square on Dec. 7, 2015 in Birmingham, England. Getty Images/Richard Stonehouse