"Shaun of the Dead" and "The World's End" star Nick Frost will appear in this year's "Doctor Who" Christmas special. In a statement, Frost says: "I'm so thrilled to have been asked to guest in the Doctor Who Christmas special, I'm such a fan of the show. The read-through was very difficult for me; I wanted to keep stuffing my fingers into my ears and scream 'No spoilers!' - every day on set I've had to silence my internal fan boy squeals." Showrunner Steven Moffat adds: "Frost at Christmas - it just makes sense!