Cannes 2012: Kristen Stewart Steps Out in Stunning Scarlet Reem Acra Gown

Getty Images

Kristen Stewart definitely saved the best for last. After she wore a Balenciaga print gown for the Cannes premiere of On the Road on Wednesday night, we thought she couldn't top the scrollwork print dress designed by Nicolas Ghesquiere.

our editor recommends

Cannes 2012: Robert Pattinson Says He Spent Two Weeks in His Hotel Room Worrying About 'Cosmopolis'

Cannes 2012: 'On the Road' Stars Kristen Stewart, Kirsten Dunst vs. Milla Jovovich in a Red Carpet Showdown (Poll)

Cannes 2012: Kristen Stewart, Kirsten Dunst Step Out for 'On The Road' Photo Call

PHOTOS: Cannes Day 8: 'On the Road' Photocall, '7 Days in Havana' With Benicio del Toro

We were wrong. The winner was her bright crimson Reem Acra (pre-Fall 2012 ) crepe gown -- majorly sexy both coming and going with a very deep V neckline and a sheer lace back -- worn at Friday's premiere of Cosmopolis.

But like a good movie star, Stewart avoided being photographed with her boyfriend, Twilight co-star Robert Pattinson, who toplines the new film by David Cronenberg. Instead she posed with her arm around Road co-star Tom Sturridge, who is dating actress Sienna Miller.

We don't know how Pattinson fared on the carpet, wearing his slick Gucci suit, but he definitely had trouble keeping a straight face at the Cannes press conference earlier.

According to Dana Kennedy, a reporter based in the South of France, the famous leading man/sex symbol acted more like a goofy, silly 11-year-old as he tried to answer questions from the international press. “He giggled throughout the press conference, frequently whispering to Cronenberg and erupting into more self-conscious laughter.”

STORY: 'On the Road' Stars Kristen Stewart, Kirsten Dunst vs. Milla Jovovich in a Red Carpet Showdown

Cronenberg nixed any suggestions that Cosmopolis character, Eric Packer, who spends most of his time in his coffin-like sretch limo be compared to Pattinson's life in a fishbowl as a result of his teen idol status or his Twilight vampire role ...

"The character of Eric Packer is a real person with a real past and it is Cosmopolis, not Twilight," Cronenberg told reporters.