After teasing the video for several days on their YouTube account, Topshop has finally revealed #whosthatgirl, the mystery star of their first-ever Christmas film: Kate Bosworth! The short film, directed by Michael Polish (Kate’s man) and inspired by Michelle Pffeifer’s famous piano scene in The Fabulous Baker Boys, has Bosworth in a very festive red party dress, singing the iconic holiday song “Winter Wonderland,” to a room full of awe-struck onlookers. “This project brings together two important aspects of my life: cinema and fashion,” Bosworth said in a statement. “I hope everyone enjoys watching it as much as we did making it!” The dress and shoes Kate wears in the video will be available as a special made-to-order on topshop.com to coincide with the new Topshop store opening in Los Angeles next February. And you can download Kate’s song on itunes.com now. Watch the clip above for a dose of holiday spirit, and scroll down for the star’s special message to InStyle readers.

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