10 Doctor Who Episodes That Were Almost Completely Different
3. Twice Upon A Time
As many Doctor Who fans are aware, we almost didn't get a 2017 Christmas special at all. Reigning showrunner Steven Moffat was intending to end his tenure with the Series 10 finale in July, and new showrunner Chris Chibnall didn't want to start at Christmas.
As such, Twice Upon A Time was almost different in that it almost didn't even happen, but even when Moffat did start to write, things changed significantly along the way.
The episode sees the return of the Twelfth Doctor's Series 10 companion, Bill Potts, and she has a large role within the episode - but this wasn't always the case. In fact, Moffat was already making good progress on his script when he thought about adding in Bill, with him deciding that the story needed the perspective of her character.
On top of not featuring Bill, Twice Upon A Time nearly didn't feature Clara, either. She appears for a brief cameo at the end of the episode, but according to Moffat, this was "complicated to arrange", because at the time, actress Jenna Coleman was busy filming her own TV series, Victoria.