The one thing Kate Middleton never wears

Kate Middleton is a fashion icon and regularly steals the show for her outfit choices, but there is one thing she never wears – colored nail polish.

For her public duties, the Duchess of Cambridge is always pictured with au naturel nails, and there is strict reason for this.

According to OK! magazine, colored nail varnish and fake nails are not part of the royal etiquette, and are typically considered to be “vulgar."

On the rare occasion that her nails do have a slick of polish on them, she opts for a nude shade, similar to the Queen’s personal favorite.

Queen Elizabeth is said to have worn Essie's Nail Lacquer in Ballet Slippers since 1989.

According to the brand's website, Queen Elizabeth's hairdresser wrote to the brand's owner, nail polish-mogul Essie Weingarten, asking for a bottle of the light pink polish as she didn't want to wear any other.

The only time Kate has deviated from the Ballet Slippers shade was her wedding day to Prince William.

On the big day, her manicurist Marina Sandoval revealed her nails were a custom mix of Bourjois So Laque Nail Enamel in Rose Lounge and Essie Nail Polish in Allure.

It’s not just the Duchess and the Queen who have been seen abiding by the nude nail varnish dress code.

Prince Harry’s girlfriend Meghan Markle was seen with natural nail shades during her first public appearance at the Invictus Games.

This article originally appeared on The Sun