Mark Williams as Brian Williams
It was awesome when we finally got to know Rory Williams’ father, who also happens to be Ron Weasley’s father, because of timey wimey. And the actor is playing different characters, but that’s beside the point. From just a storyline perspective, could you imagine the change in dynamic of the TARDIS if the grieving father of Amy and Rory was travelling with the Time Lord partially responsible for their deaths? Jeez. TENSION MUCH?