Elle Fanning, who just arrived in Cannes for the debut of her latest film, Sofia Coppola’s The Beguiled, has described herself as “a unicorn flower child at heart, mixed with a schoolboy and the occasional Cali surfer dude.” That has translated to some whimsical, fashion-forward red carpet looks, including the Vivienne Westwood gown she wore for tonight’s opening ceremony of the Cannes Film Festival. It’s the first look that actually features Fanning’s favorite mystical creature: If you look closely, you’ll see a unicorn hand-painted on the train in candy pink. In fact, the unicorn was Fanning’s idea—she worked with Westwood and Andreas Kronthaler on the custom gown, which is a modern reinterpretation of Westwood’s iconic Bird of Paradise dresses from Spring ’05. Here, she gave Vogue an exclusive behind-the-scenes look at the making of the gown and the story behind it.

In The Beguiled, Fanning’s wardrobe consists of 19th-century American staples like Victorian lace dresses and ruffled blouses. But Westwood’s gown takes her a little further back in fashion history: It was originally inspired by 17th- and 18th-century salon culture, particularly the corsets, bustles, and exaggerated silhouettes women favored at that time. Fanning’s strapless, corseted gown comes in “snowdrop white” draped and bustled duchesse satin with a hand-painted design that was loosely inspired by Frans Hals’s 1624 painting The Laughing Cavalier. The artwork depicts a young man in an extravagant silk costume embroidered with bees, arrows, lover’s knots, and tongues of fire, which were meant to symbolize “the pleasures and pains of love.” Westwood’s symbols celebrate femininity and Fanning’s personality: There’s a shooting star named Elle; the planet Gaia, Westwood’s signature orb; and, of course, the requested unicorn, all in pretty shades of pink.

Westwood’s team says 10 people worked on the dress, which took more than 300 hours to finish by hand; it was completed over the course of 10 days. Check back later this week for more of Fanning’s best looks in Cannes, plus all the biggest news from the film festival. [Source]