Actor Peter Capaldi has given a young Doctor Who fan his “favourite present ever” after sending him a personal message from the outgoing Time Lord.

Author Brian McGilloway said his sons David, nine, and 11-year-old Tom woke up on Christmas morning to letters from Doctor Who which moved the whole family.

The letters contained greetings, drawings and a signed picture of Capaldi – and a note addressing the ‘icky’ business of regeneration.

The Doctor Who Christmas Day special marked the end of Capaldi’s tenure as the Time Lord, with Jodie Whittaker regenerating as the first female Doctor in the final moments of the episode.

Mr McGilloway, 43, tweeted: “Peter Capaldi is my 9 year old son’s fav Doctor Who 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.”

He said his son was “thrilled” by the letter, which he described as his “favourite present ever”.

The message, signed by Capaldi, states: “Xmas is always good fun. Well not always. Not every single second.

“Regenerating is not completely good fun.

“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.

“The new doctor always becomes your favourite 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.”

Mr McGilloway, who is also father to Ben, 14, and seven-year-old Lucy, said: “David particularly loves Peter Capaldi and was devastated about his regeneration.

“There’s so much detail in the letter, I was left with a lump in my throat.”

The best-selling thriller and mystery writer, who teaches English at Holy Cross College in Strabane, West Tyrone, did not reveal the content of his other son Tom’s letter, which he said was “more personal”.

He did reveal that this was not his family’s first brush with the Time Lord.

“Earlier in the year I met Christopher Eccleston in Belfast and told him my family were such fans,” he said.

“Around October he facetimed them all and spoke to them each individually as Doctor Who. It was such a lovely thing to do.”