Peter Capaldi asked for his finals scenes as Doctor Who to be changed at the last minute.
The 59-year-old actor - who has portrayed the Time Lord for the past four years - will bow out of the sci-fi series in the festive special on Christmas Day (25.12.17) but he asked the departing show runner Steven Moffat if his final moments could be tweaked because he didn't feel "comfortable" with it - but the re-write meant he had to learn his lines overnight.
Speaking on BBC Radio 2 this morning (20.12.17), Peter said: "We're all very concerned about how the Twelfth Doctor leaves us. We're hypersensitive about trying to make it the best we possibly can. I had sort of expressed a little discomfort about one of the scenes leading towards the end - and he rewrote it. He rewrote it completely, and quite brilliantly, overnight. Which is fantastic. The downside is I had to learn it overnight!"
Peter will leave the show alongside Steven at the end of the year and he has admitted that it will be a huge blow to the show when he's gone because he's a "brilliant writer."
He explained: "He's one of the wittiest, funniest people I've ever met. I think Steven could have easily been a stand-up comedian in another life. One of the most entertaining things that I'll always remember about Doctor Who is that at the start of each season, he asks me round to his house and he will tell me what's going to happen to the Doctor.
"He will go through all 12 episodes, just himself in his kitchen describing it all, and he's absolutely hilarious. It's doubly hilarious as you go on; obviously some of the episodes don't turn out quite as well as he described them, or have a little less money, or are a little less focused. But he's just a brilliant brilliant writer."
Jodie Whittaker will take on the role of the time-travelling alien from next year.