Princess Diana is the ultimate royal style icon - here's 27 photos to prove it

At just 19 years old, Lady Diana Spencer was already a style icon before she officially became a royal. In this photo, she was working as a nursery teacher (albeit a remarkably stylish one), wearing shades of purple in a tailored, collegiate style.

The day her engagement to Prince Charles was announced, Princess Diana wore a royal blue skirt and matching blouse paired with a black clutch at Buckingham Palace.

Making yellow dungarees look incredible, Diana paired them with a Liberty print shirt and pink espadrilles at a polo match in 1981. It was an eclectic mix, but she made it work effortlessly.

Diana's famous gown on her wedding day in July 1981 was made of British-woven silk and featured a dramatic 25-foot train. The dress was designed by the husband-and-wife duo David and Elizabeth Emanuel, creating a magical bridal moment.

Only days after her first pregnancy was announced, the 20-year-old Princess attended the Victoria and Albert Museum in November 1981 wearing a lilac Bellville Sassoon gown, looking just like a fairy princess.

Diana styled out this iconic black sheep jumper in 1982, proving that a winter staple does not need to be boring.

Proving that simple dresses can truly shine, Diana looked beautiful in a single-shoulder Bruce Oldfield silk gown in a shade of bubblegum blue. Headlines were made for good reason.

Attending a Genesis concert in February 1984, Diana wore a sharp white tuxedo by Margaret Howell accented with a black bow.

Teal is a timeless shade, and Diana was ahead of her time with this single-shoulder gown in 1985. For an appearance in Melbourne, Australia, she famously wore an emerald and diamond choker across her forehead as a tiara, showing her unconventional approach to royal style.

One of her most celebrated looks was this strapless, deep blue dress designed by Murray Arbeid, styled with vibrant fuchsia gloves. Embellished with stars, the dress offered a theatrical appeal perfectly suited for the premiere of The Phantom of the Opera in 1986.

Making pink gingham pop, Diana posed outside on the steps of her Highgrove country home wearing a hot pink sweater layered over a white long-sleeved blouse paired with matching gingham trousers.

Channeling a bold aesthetic, Diana wore striking red leather trousers to watch The Phantom of the Opera in February 1987.

Strolling through the Guards Polo Club, Diana kept things casual and off-duty in jeans, a sweatshirt, and a crisp blazer. It remains an iconic Pinterest moment to this day.

Looking relaxed while on holiday in Necker Island in April 1990, Diana kept her style effortless in a loose leopard-print dress.

The combination of lemon yellow and baby pink suited Diana wonderfully in this dress, which she wore while visiting AIDS patients at a hospital in Rio De Janeiro in April 1991.

Diana was never afraid to embrace bold prints. Arriving at a concert in November 1991 in a vibrant rainbow skirt suit, she cemented her status as a royal style icon.

Green was certainly one of Diana's signature colours. This forest green co-ord added a rich pop of colour to her outfit during a visit to the British School of Seoul in South Korea, complete with matching court shoes.

Wearing an elegant yellow and blue halterneck dress by Catherine Walker to the premiere of Far and Away in July 1992, Diana looked every bit the Hollywood star.

Looking sharp in a peppermint suit, Diana suited this classic '90s roll-neck and blazer combination upon arriving in Zurich in March 1993.

Looking like a real-life Barbie, Princess Diana stepped out in 1993 wearing a hot pink frock coat and matching skirt.

No list would be complete without the iconic 'Revenge Dress' from 1994. The glowing 32-year-old Princess arrived at a Serpentine Gallery benefit in an off-the-shoulder black dress by Greek designer Christina Stambolian, making an unforgettable statement.

Diana embraced off-duty London style while shopping in Knightsbridge in October 1994, pairing white jeans and loafers with sunglasses and a tailored blazer.

Stepping out in a chic, short white dress by Versace, Diana showcased her growing fashion confidence during an appearance in Italy.

Mixing athleisure with everyday loungewear, Diana effortlessly styled a Virgin Atlantic sweatshirt with bright orange cycling shorts, capturing classic '90s street style.

Attending the Met Gala in December 1996, Princess Diana looked radiant in a navy John Galliano for Dior slip dress as she stepped out following her divorce from Prince Charles.

Diana's casual looks were entirely effortless, as seen in this pastel jumper and white jeans combination spotted as she left the gym in May 1997.

In July 1997, Diana attended one of her final public events at a gala celebrating the Tate Gallery's Centenary, wearing a black Chantilly lace gown by Jacques Azagury embellished with delicate sparkles.