French jeweler Piaget is celebrating the 20th anniversary of its Possession range with fashion 'it girl,' Sienna Miller as its new cover star.

Clearly meant to target the next generation of customers, the ads show an angelic-looking Miller, wearing necklaces from the collection.

Shot by Raymond Meier (and styled by Elissa Santisi and Gucci Westman) in New York, the campaign is soon to be unveiled, but in the meantime, Piaget is already banging the social media drum to stir up excitement for the anniversary celebrations: a making-of video will go live on YouTube on May 17, and the jeweler has also launched a Possession-themed video contest on Facebook, //www.facebook.com/Piaget.

Miller is quickly upping her fashion credibility: she previously starred in style-laden films including Factory Girl, graced the cover of US Vogue and the campaign for the Boss Orange fragrance, while co-running the Twenty8Twelve label.

More information on Piaget's anniversary can be found at //www.piaget-possession.com.