After showing a sneak preview of The Secret Life of Walter Mitty back in August, we now have the official theatrical trailer for you. Directed by and starring Ben Stiller, the film is the story of a magazine photo editor whose dull existence is interspersed with fantasy worlds he creates while dreaming about his coworker, played by Kristen Wiig. When both of their jobs are threatened he sets out on a global adventure in search of a missing film negative. Although a little more serious than standard Stiller fare, supporting roles from Wiig and Adam Scott should keep things entertaining. The Secret Life of Walter Mitty is released in cinemas December 25.