Dakota Johnson Channels Her Inner Audrey Hepburn at the amfAR Milano Gala: See More Stars on the Red Carpet

Gorgeous for a good cause—and so retro, too! Dakota Johnson attended the annual amfAR Milano Gala on Saturday, Sept. 26, in Milan, Italy, and she modeled her best Audrey Hepburn-esque outfit for the occasion.

PHOTOS: Dakota's best red carpet styles

The Fifty Shades of Grey actress, 25, went retro in a strapless, tea-length black cocktail dress, compliments of Christian Dior, which she teamed with matching strappy sandals and a small clutch, both by Roger Vivier. A diamond strand necklace and stud earrings by Bulgari completed the elegant ensemble.

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But she wasn't the only stunner at the event! Johnson was joined by Ciara, who donned a jade-green tank, a leather skirt, and a ruffled train, all by Roberto Cavalli. She accessorized the look with Giuseppe Zanotti sandals and some arm candy—the handsome Peter Dundas, the designer behind her getup.

Not far away, Naomi Campbell steamed up the carpet in a lace, semi-sheer Maison Margiela dress, paired with diamond Bulgari bangles.

PHOTOS: Stars without underwear on the red carpet!

And then there was Alessandra Ambrosio, who kept things short and sexy in a heavily embellished, lime-hued Dsquared2 mini, teamed with Bulgari baubles, a box clutch by Elena Ghisellini, and metallic gladiator heels.

Of course, the prettiness continued inside the event, too. During the dinner—the seventh annual event in the city, which raises funds for AIDS research—Heidi Klum (in peekaboo Atelier Versace and Lorraine Schwartz jewelry) and Michelle Rodriguez cozied up to Kenneth Cole for a group shot.

Who gets your vote for best dressed at amfAR Milano 2015? Tweet with @UsWeekly using the hashtag #stylebyUs!

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This article originally appeared on Usmagazine.com: Dakota Johnson Channels Her Inner Audrey Hepburn at the amfAR Milano Gala: See More Stars on the Red Carpet