The story behind Kristen Stewart’s vintage gown on the new Diana poster

Yesterday marked the 24th anniversary of Princess Diana's death, and a few days before that, a trailer and poster for the highly anticipated Spencer movie was released.

The film, which debuts at the Venice Film Festival this week, follows Diana’s last Christmas as a Royal family member in 1991, as she prepares to tell Prince Charles that she’s leaving him.

It stars Kristen Stewart in the titular role, and from what we've glimpsed so far, it's all looking very promising, and that's not even touching on the fashion.

The trailer shows the actress in an array of gorgeous outfits, from Diana's signature two-piece suits to over-the-top ballgowns for the more formal affairs.

One such gown is the one featured on the poster, and it has a pretty incredible story of craftsmanship behind it. According to WWD, the beige organza evening gown, embellished with gold and silver sequins arranged in a floral pattern, is the echo of a dress presented from Chanel’s spring 1988 couture collection.

The dress was re-made for Spencer in the house's atelier and required an impressive 1,034 hours of work by five seamstresses. Kristen Stewart is also seen in a vintage red checkered Chanel suit in the trailer for the movie, recreating the look Princess Diana wore on Christmas Day 1993.

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.