This Doctor Who shirt illustrates a knock-knock joke that takes place at the door of the good Doctor's TARDIS. Even though this is an amusing joke on its own, you might need a Type 40, Mark 1 TARDIS for a humorous visual. If you are a fan of Doctor Who, this is the perfect shirt for you. You'll have others laughing harder at this shirt than at some of the Doctor's whimsical comments.
