Speaking to Doctor Who Magazine in the latest issue (on sale tomorrow), Moffat teased: “The Doctor’s always said he’s thousands of years old, and suddenly he’s going to look closer to what we know he secretly is. He’s going to look like an older man. A fiercer man. He won’t be the dashing young man he was a minute ago, and I think that’ll be rather exciting…”

Discussing the casting of Capaldi, the writer added: “He’s always looked like Doctor Who, how has this taken us so long?! Because the moment you say his name, you go ‘Of course!’ Because he’s got the hair, and he’s got the look, he’s brilliant, he’s known to be a fan, of course it’s bloody him!”

Moffat also hinted in the magazine: “Just as Clara’s learning to have a proper old crush on him, suddenly he’s Malcolm Tucker! … I think the fun story will be – and we have the opportunity here – is this is what regeneration can do to you. He can be very, very different … People really love Jenna, so we make the Doctor quite difficult…”

Likening the situation to Tom Baker’s first season, he recalled: “[The Fourth Doctor is] really quite difficult to take at the beginning, and you’re very grateful that Sarah and the Brigadier are there to reassure you.”

Capaldi will begin filming his first series as the Twelfth Doctor in January 2014.

Neil Gaiman has revealed that he hopes to write an episode for Series 8 and Luther creator Neil Cross has also confirmed that he will be writing at least one episode for Series 8.

> Take a look at our Series 8 summary for all the latest news and rumours.

What are your hopes for the Twelfth Doctor? Let us know below…

> Order the complete Series 7 boxset on Amazon.

Watch the Series 7 Part 2 trailer…