Royal ladies must adhere to strict fashion rules during public appearances. Modest hemlines, light-coloured nail polish and demure necklines are all well-known standard protocols when it comes to dressing for high-profile engagements, but what about headwear?
We spoke to former royal butler and etiquette expert Grant Harrold, who served as personal butler to the then-Prince Charles at Highgrove for six years, for the lowdown on what is acceptable for Princess Kate, Zara Tindall, and other royal ladies to wear.
Princess Kate and other royal ladies must adhere to strict timings about wearing hats in public
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.
Fascinators are a big no no - Princess Beatrice manages to toe the line
"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.
The Princess of Wales pictured in red at the 2025 Commonwealth Day Service
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.
Every single item Princess Kate wears is masterfully thought out
"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.
Princess Charlene might have been on royal duty on Saturday, but with Prince Jacques and Princess Gabriella joining their parents, she was also on mum duty