Ben Stiller takes a stroll through the sky in this first poster for The Secret Life of Walter Mitty, giving a new meaning to the phrase "head in the clouds". The movie follows the daydreaming nature of a photo manager who constantly escapes to his own fantasy world. Sean Penn, Kristen Wiig, Adam Scott and Shirley MacLaine co-star in an adaptation of James Thurber's classic novel, in theaters Christmas Day.