Topshop Christmas film starring secret Hollywood starlet Topshop has unveiled its first ever Christmas campaign - a film starring a secret Hollywood starlet. TelegraphPlayer_TMG9711847 This year, high-street favourite Topshop has decided to launch its first ever Christmas campaign, but it's not any old campaign; it's a super-slick film titled Winter Wonderland . IN PICTURES: Topshop Unique spring/summer 2013 But the retailer is keeping schtum as to who its leading lady is, releasing a series of mysterious teasers before the full-length film premieres on December 4. All we know is that it stars a very famous Hollywood actress with huge style credentials. Who could it be in that sparkly red dress? You can share your guess on Twitter via @Topshop using #whosthatgirl for the chance to win £500 shopping spree. IN PICTURES: The trendy 20: Party dresses Be sure to check back here each day leading up to the premiere to see more teasers, then we'll have the full film and a very special message from its leading lady on Tuesday, December 4.