Sienna, Helena, Kate Moss, and Emma Watson Party at Downing Street!

Samantha Cameron played host to A-list stars at 10 Downing Street last night. She held a cocktail party as part of London Fashion Week, and hot footed it back from the starry front row of the Burberry show to welcome guests like Sienna Miller, Emma Watson, Kate Moss, and Helena Bonham Carter. Kate had Mario Testino on her arm, while Helena was with Tim Burton, and Sienna had sister Savannah for company. Although the guests are easy to recognise, they still had to prove their identities! Click through to see the other partygoers, including Anna Wintour, Claudia Schiffer, Sir Philip Green, the Le Bons and Jemma Kidd.