Lupita Nyong'o, Natalie Portman, Julianne Moore: All the Best Looks From the Cannes Film Festival So Far

— -- The Cannes Film Festival kicked off today, and the stars attended the opening ceremony in their finest couture.

However, perhaps the most discussed gown belonged to Lupita Nyong'o, who dazzled in a custom emerald green embroidered gown by Gucci.

"It's #GrasshopperGreen for @festivaldecannes opening night. Thank you @Chopard @Gucci and Uganda's women for the hair inspiration. #NseneneSeason #cannes2015," she wrote on Instagram.

However, Nyong'o wasn't the only one who caused jaws to drop. Natalie Portman stunned in a bright red Dior dress, as did model Karlie Kloss in Atelier Versace Couture.

Here are a few other of the most stunning looks from the red carpet.

Jane Seymour

Bar Rafaeli

Natalie Portman

Julianne Moore

Karlie Kloss

Sienna Miller