During her trip to New York City, the Countess of Wessex sported some striking berry-coloured nail varnish.
This broke the royal rule that royal ladies are only supposed to wear nude or neutral nail varnish.
It is a royal rule the Duchess of Cambridge has even fallen foul of, as she was a fan of some brighter colours during her early days as a working royal.
In more recent years however, Kate has hardly ever worn nail varnish.
For her wedding, she sported a unique colour combination, which was produced by mixing two shades together.
The pure, pinky nude shade gives nails a blush-toned hue that is chip-resistant and opaque after one coat.
The Queen herself is a big follower of this rule, and she has remained loyal to her favourite Essie nail polish since 1989.
“Only nude shades, sheer whites and light pinks are allowed.
“A firm favourite of the Queen’s is Essie’s ‘Ballet Slippers’.
“In fact, for their weddings, both the Duchess of Cambridge and the Duchess of Sussex famously combined two nude nail colours.
“While Kate wore a mix of ’28 Rose Lounge’ from Bourjois and the now discontinued ‘423 Allure’ from Essie, Meghan wore a mix of CND Shellac’s ‘Unmasked’ and ‘Negligee’.
“However, both Duchesses have occasionally favoured dark red or oxblood toenails on open-toed heels.”
Despite Sophie’s slight slip on royal protocol, she has been astounding royal fans with some amazing looks during her time in New York.
The Countess rocked one of her favourite designers on Tuesday, looking sophisticated and stylish in a Victoria Beckham blazer and flared trousers.
Sophie teamed her bottle green ensemble with a ‘Rose Cloudy Floral Silk’ button-down blouse.
Teaming her attire with a pair of gorgeous leather pumps from Jimmy Choo, the royal looked very elegant.
She styled her blonde hair into a smart low ponytail, highlighting her pretty features with voluminous mascara, rosy blush and a subtle pink lip.
It’s not the first time this week the Countess has donned Victoria Beckham, opting to wear a ‘Pleated Printed Crepe Mock-Neck Midi Dress’ on Monday night.
The mother-of-two recycled her favourite dress that she last wore in 2021 to reveal the winner of the Queen Elizabeth II Award for British Design.
Other looks for the royal’s New York trip included a slick cream coat from Max Mara, layered over a figure-flattering black leather dress.