The One Beauty Rule That Kate Middleton Must Adhere To, Apparently

This is why you'll never see the Duchess of Cambridge with brightly painted nails...

Kate Middleton has, undoubtedly, become one of the most influential women in the UK when it comes to fashion and beauty.

The Duchess is spotted in something. It’s an instant sell-out.

She changes her hair. We’re taking that photo to the hairdressers.

See: Where To Buy Kate Middleton’s Favourite Wellington Boots

But it seems as though there’s one beauty treatment that you won’t be seeing K-Middy indulge in. And that’s a fancy ol’ manicure.

Kate Middleton always opts for a neat manicure with bare, natural nails…

See: The Under-£20 Face Oil That Kate Middleton Swears By

You might have already noticed that neither the Duchess of Cambridge or Queen Elizabeth are spotted with brightly coloured nail varnish or fake nails.

And, according to sources that have spoken to OK!, it’s got everything to do with royal etiquette.

See: Kate Middleton Turns Heads At Paddington Station For One Reason

The publication reports that a false mani’ and coloured polish is deemed ‘vulgar’ by the royal family.

But there is one shade of nail varnish that has got the royal stamp of approval.

According to the report, beauty brand Essie claimed that the Queen’s hairdresser sent them a letter to request their shade Ballet Slippers.

Apparently it’s ‘the only colour Her Majesty would wear.’

The super pale nude/pink shade will go with practically any outfit, and Queen Elizabeth is said to have been using it since 1989.

In fact, Kate seemed to follow in the Queen’s footsteps by requesting the very same shade for her wedding day back in 2011.

And at just £7.99 from high street beauty hotspot Boots, you can snap some up for yourself.

Yup. We predict a sell-out.

We mean, who wouldn’t want royal nails…?