I suspect there may be some "regenerating timelords take the appearance of other people" handwave going on.
I don't see why there even needs to be a handwave! Audiences at this point should be able to grasp the idea of an actor who plays more than one character within a long-running franchise.
no subject
I don't see why there even needs to be a handwave! Audiences at this point should be able to grasp the idea of an actor who plays more than one character within a long-running franchise.