EXCLUSIVE AT NET-A-PORTER.COM. Erdem's 'Marianne' gown has been designed for the Green Carpet Challenge which aims to place ethical fashion in the global spotlight. Crafted from naturally treated duck-egg silk-gazar, it's been digitally printed in the Netherlands with a delicate floral motif using water and energy-saving methods. The fitted waist and tiered skirt add to its romantic feel. Style yours with a box clutch and heels.