Style watchers of the British royals love to point out the fashion choices of the women in the family. Through the many years they’ve been in the public eye, some have graced the headlines as trendsetters and even fashion icons.

But buried beneath the designer labels, sophisticated looks, and high end pieces, are rules. You knew that already though, didn’t you? We’ve learned about tiara protocol, manicure musts, wedding gown expectations, and Queen Elizabeth’s wardrobe habits.

A lesser known rule that you may not have been privy to however, has to do with royal women’s coats. If you’ve been paying attention, it’s possible you’ve noticed that Duchess Kate keeps her coat on during public events. It’s not always because it’s freezing outside either.

Most recently, Kate Middleton has been in the news as she and husband Prince William traveled to the Nordic region of Europe. Fashion publications quickly took notes on her gorgeous collection of outerwear. Media outlets also seized upon a photo of the duke and duchess seated indoors across from Norway’s Crown Prince Haakon and Crown Princess Mette-Marit.

Why? Duchess Kate was still wearing her coat, buttoned up to the neck while inside. As stylish and extensive as her outerwear collection is, royal protocol does not permit senior-level women to remove their coats in public. It is considered unladylike to do so during royal engagements.

It can’t be done in front of cameras either, hence the reason she is wearing it in the photo. Off camera and out of view, it is a different story. When you think about it, you have never seen the Queen take her coat off in public either!

There is no clear timeline for when this rule came into existence, but it only applies to females. The same also applies for royal-to-be, Meghan Markle, who is still learning the ropes when it comes to dress codes and etiquette. Men, on the other hand, can do as they wish when it comes to coats and jackets.

In addition to the coat rule, there are a few other fashion no-no’s for the duchess and other women of the royal family. For example, bare legs are also forbidden when wearing skirts and dresses. While it may appear that Kate Middleton is exposing her legs, she is always wearing a pair of tights or sheer pantyhose.

Short skirts are also off limits, so you will typically see royal ladies with at least a knee-length hem on their dresses. For formal occasions, floor length hems are a must.

Since it’s a possibility that Prince William will one day be king, it’s no surprise that the duchess is on point when it comes to royal etiquette. It is rare for us to see her veer from tradition and rules, but things could certainly change in the future. Click on this video to hear more about this steadfast rule.

For now, fans of royal fashion can keep admiring Kate Middleton’s coats and Meghan Markle’s wardrobe too, because both women have clearly made their mark. And now you know that the duchess hasn’t been perpetually cold everywhere she goes.

Did you know about this part of the royal dress code? What do you think of the coat rule for royal women?