Peter Capaldi was seen regenerating as the 12th Time Lord in Doctor Who on Christmas Day. But before that series returns, he plays an evil cardinal in BBC1’s ambitious new drama, The Musketeers. Here he tells us why he thrives on being a baddie…

What was the appeal for you of starring in this new 10-part series, The Musketeers, based on Alexandre Dumas’s popular characters?

“I love period stuff, I love the kind of angle they’ve taken on this and it looks great. It looks like a movie and has this wonderful cast who bring so much to it. And then I get to play the bad guy.”

Is your character Cardinal Richelieu really bad?

“Well, he’s just doing his job, which is to look after 17th century France, which no else seems to care about. The Cardinal believes France is in a state of disarray, so he’s committed to making the country and himself powerful while also protecting the King. Yes, he’s manipulative, but it’s a tough world and he’s just doing what he can to survive.”

The Cardinal is being helped in his deviousness by the beautiful but dangerous Milady (played by Maimie McCoy). What are her strengths?

“The Cardinal and Milady have a special relationship and an understanding about each other’s past. Milady has many weapons at her disposal, which she can deploy and she uses each and every of them – she uses her feminine wiles to draw men into a web of her design. This world they’re living in might be all tarted up in pretty, lacy outfits – but there’s always someone waiting to kill you.”

You’ve grown a rather impressive beard for your role as the Cardinal. Has it been easy to get used to?

“I’ve never had a beard before like this. I feel I should have a T-shirt on saying: ‘This is for a job’. It’s weird when you see a guy approaching you, especially in Crouch End, with the same beard. Do you catch his eye? Do you not? You wonder if you’ve made the same life choices. And you look at him and think: ‘I don’t wanna be that guy!'”

So you have a beard, but are you envious that you don’t get to be a sword-wielding musketeer?

“Towards the end of this series I might surprise you all with a piece of admirable sword work. But, no, I don’t mind. I love walking around in black leather outfits and generally playing a nasty piece of work. I get to poison and torture people and have them killed… what more could you ask for?”

Did you enjoy filming The Musketeers in Prague?

“It’s such a wonderful city. It’s so haunting and there’s so much there. It’s one of those places that stays with you. It was a privilege and a joy to go out there.”

What do you think it is about Alexandre Dumas’ stories of The Musketeers that people have enjoy for all these years?

“There’s a real mystery surrounding these stories, there’s something at the heart of them that is attractive to people. There’s something about this world and these young musketeers trying to make their way in that world – with violence – that is quite compelling.”

The Musketeers starts on Sunday, January 18 at 9pm on BBC1.