designer Zac Posen think Cate Blanchett is the best-dressed celebrity . Posen "from Zac" has worked with celebs from Gwyneth Paltrow to Michelle Obama, but it's actress Cate Blanchett who tops his list of Hollywood's best-dressed. “She exudes elegance and glamour,” says the fashion designer, 32. Online Extra: Posen, the newest judge on Project Runway (Lifetime, Thursdays), reveals the No. 1 item every woman should have in her closet. "Every woman is different, but I believe that every woman should have what I call a 'silhouette statement,' which is an LBD [Little Black Dress]. It's always chic, it's always a great staple, and you can find it in many shapes and price points. It has a sophistication to it that is international. There's safety and mystery in wearing in LBD."