16. WORST: Katy Perry failed to hit the high note a la mode at the Jason of Beverly Hills party in Los Angeles, wearing a studded leather jacket over a floral frock with boots. 18. BEST: Keira Knightley dropped jaws in Chanel Haute Couture at the London premiere of Anna Karenina, finishing off the angelic look with Rupert Sanderson heels and Chanel jewels.