As fans of the show already know, the regeneration process faces every Doctor when their time has come – and fans were left gasping at Capaldi’s, given how intense it was.
So intense, in fact, that he had to write to David McGilloway, from Londonderry, to ease his worries about the regeneration process, which he said was like ‘having bad flu’.
David’s father, Brian, posted the handwritten note that the young fan opened up with his presents on Christmas morning.
PeterCapaldi is my 9 year old son’s fav #DoctorWho and he was dreading his regeneration. And then he got this letter with some words of comfort from the Doctor himself among his Santa presents. Such a kind man,’ the Dad wrote.
David told the BBC: ‘The letter was just so magical, the envelope it came in, Peter Capaldi drew a Dalek on it and it said my name on it,’ he added.
The letter read: ‘Dear David. I hope you are enjoying a very merry Xmas. Xmas is always good fun. Well not always. Not every single second. Regenerating is not completely good fun. And it usually happens about Xmas-time.
‘But you know what? Even though it can be a little bit icky (like REALLY bad flu) it has always, always turned out good for Doctor Who. The new Doctor becomes your favourite Doctor and the one that goes … well he never really goes, he is always there, somewhere in time and space and if you think about him hard enough you’ll see him and he’ll see you.
‘It’s like the Doctor says, everything ends and it’s always sad. But everything begins again and that’s always happy. Be happy. So have a brilliant Xmas, a happy New Year and a wonderful life – I’m sure you will,’ he said as he rounded the letter off.
Fans of the show finally had the chance to see the first female Doctor in action as Jodie Whittaker made her debut on the show as Capaldi exited.
It followed emotional scenes in the TARDIS as Capaldi delivered his final monologue before declaring ‘I let you go.’
Jodie, meanwhile, began her time on the show with a shocked expression as she uttered her first words: ‘Oh brilliant!’ before attempting to take control of the Tardis.
Although it all ended on a cliffhanger as the Doctor’s new incarnation managed to crash it before the credits had even rolled – leaving her separated and plummeting to earth.
Got a story?
If you've got a story, video or pictures get in touch with the Metro.co.uk Entertainment team by emailing us [email protected], calling 020 3615 2145 or by visiting our Submit Stuff page – we'd love to hear from you.