Exiting 'Doctor Who' star comforts 9-year-old fan with touching letter

Regeneration is such sweet sorrow, but for Doctor Who, it’s a part of the natural order.

With one Doctor (Peter Capaldi) exiting the long-running show to make room for the new Doctor (Jodie Whittaker), one 9-year-old fan was particularly torn up about saying goodbye to his favorite incarnation of the Time Lord. To ease his angst, Capaldi sent the boy a Christmas letter he’ll likely never forget.

Brian McGilloway of Strabane, Ireland, posted a photo on social media of what his son, David, found “among his Santa presents.”

“Dear David, I hope you are having a very merry Xmas,” Capaldi began his letter. “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 Dr. Who.”

Capaldi has been the BBC’s resident Doctor since 2013, but the show’s Christmas special saw the time-and-space traveler regenerate to become the next iteration, played by Whittaker — the first female Doctor.

“The new doctor always becomes your favorite 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,” Capaldi wrote to David. “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. All the best, Peter Capaldi, Doctor ?”

Whittaker will appear as the 13th Doctor alongside freshly cast Bradley Walsh, Tosin Cole, and Mandip Gill.

In the face of a few angry fans to the casting of a female lead, Capaldi said, “I saw what [Whittaker’s] done and she’s great, so I think it’s in really good hands. I’m glad people were moved by the idea of her.”

The actor also revealed to EW his advice for Whittaker. “I said just enjoy it because it’s absolutely incredible,” he said during San Diego Comic-Con. “She’ll be fabulous. It was lovely to speak to her and see how much affection and passion she has for the show. She’s going to be brilliant.”