Princess Diana was the first royal to wear this

(Image credit: Getty Images)

We all know Princess Diana's iconic style, but what few can truly appreciate is just how groundbreaking it was. She was the first royal to break the strict etiquette, including the time she ditched gloves, or wore two watches.

Of course, one of her most famous looks was the Revenge dress, however there was another headline-grabbing outfit she wore before that.

I'm referring to the stunning double-breasted suit Princess Diana donned for a concert in aid of the Prince’s Trust on April, 29, 1990.

It was oversized and featured a silk lapel, as well as embellished buttons, and she teamed it with silk navy pumps and a matching clutch bag.

At the time, it was a rather huge deal, because it was the first time a royal had been pictured wearing trousers to an evening function.

(Image credit: 1990 Julian Parker)

Simra Khan-Jackson, Founder of Khan Jackson and Owner of Vulture London, told Woman & Home, 'Diana’s power-suits mirrored her bold, unique, and influential personality. They not only looked ultra-stylish but were also practical, allowing her to carry out her duties as a Princess, which were not always glamorous'.

'Diana had a daring sense of fashion, reflecting her nonconformist attitude to the world. She wasn’t afraid of being different or the ever-increasing media controversies. She claimed ownership of her life and wasn’t shy from speaking up about her struggles. Her power-suits were designed to fit her unapologetic and confident personality,' she added.

The late royal would go on to wear many power suits, and paved the way for future generations to ditch the fashion rule book. For example, Meghan Markle herself wore a black suit for her first evening engagement after marrying Prince Harry.

Penny Goldstone

Penny Goldstone is the Digital Fashion Editor at Marie Claire, covering everything from catwalk trends to royal fashion and the latest high street and Instagram must-haves.

Penny grew up in France and studied languages and law at the Sorbonne Nouvelle University in Paris before moving to the UK for her MA in multimedia journalism at Bournemouth University. She moved to the UK permanently and has never looked back (though she does go back regularly to stock up on cheese and wine).

Although she's always loved fashion - she used to create scrapbooks of her favourite trends and looks, including Sienna Miller and Kate Moss' boho phase - her first job was at MoneySavingExpert.com, sourcing the best deals for everything from restaurants to designer sales.

However she quit after two years to follow her true passion, fashion journalism, and after many years of internships and freelance stints at magazines including Red, Cosmopolitan, Stylist and Good Housekeeping, landed her dream job as the Digital Fashion Editor at Marie Claire UK.

Her favourite part of the job is discovering new brands and meeting designers, and travelling the world to attend events and fashion shows. Seeing her first Chanel runway IRL at Paris Fashion Week was a true pinch-me moment.