23 Times Cameras Caught Kate Middleton Off Guard

8. You must always wear a hat.

When it comes to formal wear, Kate is expected to always have headwear on. Back in the day, female royals would never even leave the palace without some sort of headpiece, but as times have changed, so have the royal family and female royals are only expected to wear headpieces to special affairs like Ascot, weddings and church ceremonies.

Diana Mather, a senior tutor for The English Manner etiquette consultancy, told the BBC last year the history behind the rule: “Up until the 1950s, ladies were very seldom seen without a hat as it was not considered ‘the thing’ for ladies to show their hair in public. But all that has changed and hats are now reserved for more formal occasions.”

The same rules apply for tiaras. You will be assigned your own diamonds but this only happens after your wedding. So you might start seeing Meghan in a tiara more often.

“The old rule is that hats are never worn indoors after 6pm, because that is when the ladies changed into evening dress, and tiaras and the family jewels would come out,” she added.

“Flashy diamonds and tiaras are not worn during the day, and only married ladies wear tiaras. For married ladies, it was a sign of status and would show you were taken and not looking for a husband.”