Ballet star Misty Copeland has just unveiled that she is joining the cast of Disney’s The Nutcracker And The Four Realms , the Lasse Hallström-directed pic based on the famed story. The live action pic is being penned by Ashleigh Powell. Copeland will play the lead ballerina role in the sole dance sequence in the film. Disney in March set Hallström to direct the pic, based on E.T.A. Hoffman’s Christmas Eve tale about a young girl who finds a Nutcracker doll among the family’s gifts and is charged by her parents to take special care of it. Under the cover of darkness, the Nutcracker comes to life, along with an evil Mouse King with seven heads, introducing Marie to the magical world of toys and the brave Nutcracker who will change her life forever. Mark Gordon is producing, and Lindy Goldstein is executive producing. Sam Dickerman and Allison Erlikhman are overseeing the project for Disney and Sara Smith is overseeing for The Mark Gordon Company. In May, Deadline scooped that N