Filming on the Doctor Who Christmas special, Twice Upon A Time, took place over the summer, and a few set reports from the production have gone live. And in the midst of them is outgoing executive producer and writer Steven Moffat’s admission that Pearl Mackie’s Bill wasn’t originally going to be in the episode.
Instead, her involvement “came to me later on actually”.
“I was just starting into the script and we had Mark [Gatiss’] character and we didn’t have Bill and I was thinking ‘it’s just proof of format again’. You need someone to whom to explain”.
“Not to explain it to the Doctor; that’s not what the companion does at all. The companion makes it fun”.
As such, Moffat re-introduced Bill in later drafts of the script, including the final shooting script. Including moments where she gets to tease the current Doctor about his earlier guise, played in the episode by David Bradley.
All will be revealed on Christmas Day, when Twice Upon A Time screens…