Kristen Stewart Goes Topless, Smiles in Behind-the-Scenes Video for Balenciaga Rosabotanica

Topless and loving it! Kristen Stewart has stripped down for a sexy new Balenciaga Rosabotanica ad. In a behind-the-scenes video of the photo shoot, the 23-year-old actress and spokeswoman for the brand broke out into smiles on set while posing for the risque campaign.

Rosabotanica is the second fragrance in the collection, and Stewart says the scent is more "lived-in" than Florabotanica. "It's very much in keeping with the story," the Twilight star explained in the video. "In the first one, it was very fresh. It was really clean and very bare in your face. In this, it's a little more lived in. It's like she knows the environment so well that when the lens steps in to take a look at her, it's like, 'I've been here in my world for so long, now who's looking at me?'"

During her shoot, the Snow White and the Huntsman star didn't seem to mind who was looking at her. She looked happy between photos while getting prepped for artsy ad. The On the Road actress had colorful flowers and vines taped to across her bare chest, back and arms.

"It looks like the vines are starting to grow into her and they're becoming a part of her," Stewart said of her character for the ad. "She's clearly very comfortable there and owning it a little bit more."

In another shot, she wears a cleavage-baring, low-cut black dress and smiles for the camera. "What I like about this is that I didn't have to turn into a different person," Stewart said of teaming up with Balenciaga. "The point was to capture something natural. If you ever feel like you're forcing something or trying to get the shot, suddenly it's just not fun anymore."

Staying true to herself, Stewart can also be seen grabbing her hair between takes -- a move she and ex-boyfriend Robert Pattinson are both famous for.

Go behind-the-scenes of Stewart's Balenciaga Rosabotanica ad campaign in the video above.