Princess Diana was the first royal to wear this

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.

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.