Over the years, there have been countless familiar faces that have made guest appearances on Doctor Who, including the likes of Bill Nighy, Andrew Garfield, Maisie Williams, and Olivia Colman. If Russell T Davies gets his way, there will be one more added to the list by way of DCU star Viola Davis, but as of right now, that’s nothing more than a pipe dream for the showrunner, who recently called Davis “one of the greatest actors in the world.”