Kristen Stewart Flaunts Cleavage in Plunging Red Gown

Kristen Stewart attends the 'Cosmopolis' Premiere during the 65th Annual Cannes Film Festival at Palais des Festivals on May 25, 2012 in Cannes, France.  Venturelli/WireImage

Red-hot stunner!

Although she doesn't star in the upcoming sex-and-violence filled Cosmopolis alongside her beau Robert Pattinson, Kristen Stewart certainly stole the show at the premiere's red carpet.

In Cannes, France on Friday, the Snow White and the Huntsman actress, 22, got decked out in support of her actor boyfriend and flaunted her assets in an extremely low-cut, cleavage baring Reem Acra gown.

Kristen Stewart
Kristen Stewart on May 25, 2012 in Cannes, France. Andreas Rentz/Getty Images)

She complemented her look with a matching red lipstick and wore her hair up, which showed off the dress' sheer, lace back.

Kristen Stewart back of dress
Kristen Stewart shows off the back of her dress during at the 'Cosmopolis' Premiere on May 25, 2012 in Cannes, France. Mike Marsland/WireImage

At the event, Stewart worked her sexy red ensemble alongside Pattinson's BFF and her On the Road costar, Tom Sturridge. Absent from the red carpet: Sturridge's pregnant fiancee Sienna Miller, who is expecting the couple's first child this year.

On Wednesday, Stewart and Pattinson packed on the PDA at the On the Road afterparty, where they were spotted getting cozy on a sofa in the venue's VIP section.

"They looked really comfortable, sitting closely and chatting," an onlooker tells Us Weekly about the Twilight Saga costars. "He was talking to her and not paying attention to anyone else. Every now and then she would laugh and he would smile at her."

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