Sienna Miller is Vogue UK's December cover girl

December's issue of Vogue takes a decidedly glamorous feel with Sienna Miller as its glittery cover girl. Inside the mag, the pint-sized beauty discusses her messy apartment, Twenty8Twelve and being a muse for designer Matthew Williamson. "Five years ago, I cut out a picture from a magazine of a pretty blonde girl with a green jacket on. My sales director saw it and told me that the girl, a friend of hers, was a young actress. I subsequently met her at the premiere of Cold Mountain. She was all dressed up in Dior with ice cream down her front. It was love, " Williamson says of Miller. Too cute!