Doctor Who: 10 Things You Never Realised About Series 8

9. Patrick Troughton's Son Is In The Christmas Special

The people watching the Doctor Who Extra videos on the BBC iPlayer or YouTube already knew that Second Doctor Patrick Troughton's son, Michael, appears in Last Christmas. However, not all fans have the same access or time to dedicate to the show, so some may have missed this genetically familiar face. Michael played Professor Albert Smithe, who is part of the scientific team at the North Pole base crawling with Dream Crabs. Michael's brother, David, has previously appeared in three Doctor Who episodes - The War Games, Curse of the Pelodon, and Midnight. Another interesting casting note about Last Christmas: Dan Starkey plays one of the elves, saving himself from hours in the make-up chair for his regular character, Strax. And actors aren't the only thing the show reuses...