The extremely strict public rule Princess Kate never breaks

Hats all round!

He explained that for formal engagements, such as the Commonwealth Day Service held at Westminster Abbey last year, hats are a must.

Royal protocol dictates that hats must be worn from 6 am until 6 pm sharp. The rule is thought to date back to the 1850s when it was considered improper for upper-class and noble women to show their hair in public.

Grant clarified: “There was a rule that stated ladies could wear hats from the morning at 6 am until 6 pm. After this, they would wear tiaras if they were married. If they didn’t wear tiaras, this would mean they were single and looking to mingle. Royal women follow this old etiquette rule.”

“It does depend on the occasion, the late Queen used to wear hats all the time, and the Princess of Wales and Duchess of Cornwall wear them from time to time,” he acknowledged. “On general visits, they tend not to wear them, but on more official occasions, they will.”

Banned royal headpieces

There is another piece of headgear that is banned, despite what the royal ladies’ preferences might be.

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“Whenever there is a royal event at Westminster Abbey or a ceremony, they will wear hats. It’s important to mention they don’t wear fascinators. Even at Ascot, fascinators aren’t encouraged,” Grant said, speaking on behalf of Genting Casino.

Princess Beatrice often teases this race day rule by wearing expertly crafted oversized headbands that double up as hats.

Princess Kate’s golden style rule

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Princess Kate follows another rule when attending important diplomatic occasions – but this one is unwritten.

Prince William’s wife often tends to wear red at important and stately engagements. Case in point: her coat dress by Catherine Walker paired with a matching hat by Gina Foster on Commonwealth Day.

Colour expert, personal stylist and fashion commentator Marina Thomas explains this is something Kate’s late mother-in-law, Princess Diana, also did.

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“One reason Kate may be choosing to wear red is due to it symbolising courage, willpower and sacrifice,” Marina told HELLO!.

“This symbolism dates back to the Spartans, Persians, and later the Romans, who all wore scarlet in battle.  Wearing red certainly portrays confidence and a willingness to be seen and noticed.