Anyone else still thinking about Keira Knightley's backless green dress from Atonement, 13 years later? At the link in bio, our style editor examines why the backless trend became an unlikely Keira Knightley Green Vintage Evening Dress in Movie Atonement Celebrity Dress TheCelebrityDresses A line Strapless Cut Out Black White Polka Dot Prom Dress with Bows Slit S9057P Prom Dresses Stacees Anyone else still thinking about Keira Knightley's backless green dress from Atonement, 13 years later? At the link in bio, our style editor examines why the backless trend became an unlikely