The popular fashion style you'll never see Kate Middleton wear

Catherine, Princess of Wales is a trend-setter who regularly helps turn aspiring brands into household names and causing items to sell out as soon as she steps out wearing them. However, there’s one fashion staple that you’ll never see the stylish royal wear – and the reason why once led to her receiving some backlash.

• You’re unlikely to ever see Kate Middleton wearing an incredibly popular look, the Little Black Dress
• Members of the Royal Family are thought to be prohibited from wearing all black with the only exception being when they are in periods of mourning
• In other royal news, Princess Diana's clever hack to calm down Prince William has fans all saying the same thing

Contrary to the impression that being a royal would mean regular rules don’t apply – such as Prince Edward’s surprising grades still getting him into a prestigious university – most of the times they actually have a stricter set of protocols to follow.

The late Queen Elizabeth had a rule that all women in the Firm had to follow, and recently it was revealed that there’s an odd sunglasses rule they all must follow.

Royal rules and traditions don’t even just apply to fashion. The family have to follow strict food rules, and then there’s other customs like not being allowed to travel together if there’s multiple heirs on the same plane.

But one rule must certainly prove annoying to the likes of Kate Middleton when it comes to choosing an easy go-to outfit – and that’s because the Princess of Wales can’t turn to the trusty Little Black Dress.

Most women will agree that a classic, chic black dress is a timeless style maker. It can be sexy. It can be powerful. It can be both at the same time.

However, you’re unlikely to see Kate wearing one thanks to an old tradition which suggests royals only wear black during funerals.

And following the rule landed Kate in some bother in the past.

During the 2018 BAFTAs, women were encouraged to wear all black after the emergence of the #TimesUp movement, started after the revelations of Harvey Weinstein’s predatory ways first came to light.

The then Duchess of Cambridge was already confirmed to appear, but many wondered if she’d support the black dress code being promoted by those in the movement.

She, it would seem, couldn’t due to reasons out of her control, instead opting for a very dark green (with subtle touches of support, like a prominent black sash). Still, some social media comments at the time were unimpressed with her fashion choices.

Speaking of the long-held custom, Alexandra Messervy, founder of The English Manner, previously told InStyle, “Generally it is thought that black is not usually worn unless in mourning, although Diana Princess of Wales did occasionally wear it for evening functions.”

Indeed, Princess Diana was one of the few royals who broke the rule, causing quite the stir when she wore a black taffeta dress to a fundraising concert in 1981 - her first royal engagement after getting betrothed to Prince Charles.

Diana spoke about the incident while being interviewed for her biography in 1991, claiming Charles saw her in the dress and exclaimed, “Only people in mourning wear black!”