Lest you forget the holiday season is just around the corner, Sienna Miller is already outfitting a prime example of festive chic. Her girlie Twenty8Twelve LBD is that perfect combination of sweet and sexy, thanks to sheer sleeves and a mini hemline. Sure, it's an all-black palette, but Sienna holds our interest with a great pair of open-toe Jimmy Choo booties and a pop of shine on her hoop earrings. Add in a metallic clutch and you're dressed to hit the party circuit. Just shop our key pieces to channel Sienna's look.