She was breathtaking. A lesson in nailing the balance between exquisite glamour and understated sophistication.
"You hire Erin Walsh and you trust her," Hathaway told People, referencing her stylist. "You know, I've never been to Cannes, and I've been watching the fashion of the film festival unfold for a couple decades now. And I've noticed certain things you can never go wrong with."
"You never go wrong with a little sparkle. You never go wrong with something that looks chic and glamorous, but feels very, very comfortable. And I noticed that a lot of my favourite actresses had their first-hand experience wearing all white."
She may be taking notes from other people, but this look was unquestionably her own.
While the look was show-stopping in and of itself, it was only the beginning of Anne's fashion domination at Cannes. The next day at a photocall, Anne brought even more magic in a black-and-blue Gucci minidress.
The discotheque aesthetic featured a navy bustier top with pointed cups with a shimmering bottom in a darker shade. The tie-back detail added a touch of edginess to the overly feminine look, while Bulgari jewels and cat-eye sunglasses brought an element of playfulness.
The mod-style silhouette and cone bra was a nod to Madonna's famous Jean Paul Gaultier look from the early ’90s, but Anne's overall take gave an overwhelming sense of '60s style.
The actress' off-duty looks have been just as notable as her red carpet ones, appearing in a colourful, floral set from Schiaparelli, an oversized black suit with a white t-shirt from Gabriela Hearst when arriving to and from the airport and hotel.
Whatever era you want to call it, Andy Sachs, Mia Thermopolis, or just plain Anne, she's really redefining what it means to have a timeless appeal and aesthetic.