Benedict Cumberbatch ventures into the world of Christmas films in his new animated outing The Grinch. Here, he talks about taking on the beloved character, how he juggled it with playing Doctor Strange and why sometimes he doesn't want to use his English accent.

To the outside observer, Benedict Cumberbatch has often seemed like a serious actor.

With roles such as Sherlock, Alan Turing in The Imitation Game and even Marvel's Doctor Strange, many of his on-screen appearances have erred on the side of earnest.

But his latest part could not be more different - voicing Dr Seuss's grouchy misanthrope in the new animated film The Grinch, about a bright green furry creature hell-bent on ruining Christmas.

"He's just a fantastic, iconic character and he goes on a wonderful journey," says Cumberbatch, 42. "And it's a very heartening Christmas story whilst being very amusingly anti-Christmas to a large extent."

Most recently the famous curmudgeon was played by Jim Carrey in 2000's How The Grinch Stole Christmas.

"Admittedly, he's had a couple of outings - fantastic outings - but it's been a while and this is an animation as opposed to a live action," he said.

Watching the 2018 film, you have to remind yourself it is a British star voicing the title character because of his convincing American accent.

It's a voice that is a million miles from the one Cumberbatch normally speaks with. He is also sporting a thick moustache on his top lip in honour of the film he's currently shooting about a Cold War spy.

"I think to begin with there was talk of me making him English and I was like, 'No no no', especially if the other characters are American because then it's just the English bad guy," he says.

"Also it's just an iconically American character so I pushed for that for a little bit - but didn't have to push that hard.

"Then I just started riffing and after about four or five sessions we were all like, 'Ooh yes, that is it'."

While the idea of an English baddie is less pervasive now than it might have been during his own childhood, Cumberbatch isn't particularly interested in feeding that stereotype.

"It's interesting, I was speaking to a linguist or a dialect coach about this and there is a lot of roundedness in the American sound. It's very rich and warm and open and vowel-orientated and we are quite clipped," he says.

"We use a lot more consonants, there are more hard edges so I think culturally we are viewed as being a little meaner, a little sharper, using our heads rather than our hearts, and that manifests itself as the cliche of the English baddie, I think.

"That is pseudo-intellectual guessing, that is not linguistic scientific fact but it holds a little bit as a theory.

"It's interesting when people want you to do your own accent and I always question it a little bit, when it's something as American as this.

"Even Doctor Strange, for a while, was going to be English. And I went, 'Noooo, no, he's an American doctor - he works in New York.'

"He's American, not English, in my opinion."

Doctor Strange and The Grinch are more closely aligned than one might at first think because he was filming the superhero's latest outing while also voicing the animation.

In fact, the project overlapped with a number of his other roles and the end product was the result of voice sessions over a period of two years.

"I came in to keep working on each segment as they completed the animation and then going back to enhance any new bits that had come in," Cumberbatch says.

"It is a bizarre experience. You're in a room on your own, a recording studio. On the other side of the glass you've got the producer and director and a link to France where the great work of Illumination (the animation company behind the Despicable Me and Minions films) happens, where their studios are, and no other actors, and you're performing scenes, just your lines on your own.

"Weirdly, it gives you a lot of freedom. You have to really put your imagination into the context and what the other people are going to be doing and you build a very close relationship with the director."

The lengthy period of time meant he was frequently working on other projects when he was called to the studio, so he would dip in and out of the character.

"I was doing Avengers, Patrick Melrose, prep for Ironbark (the Cold War film that requires his bushy 'tache), Brexit, a drama I did about Dominic Cummings and all of that, very different worlds to occupy to this," he says.

"That is one of the fun things and I have always tried to foster that in my career, just the variety and the mad differences between what I choose to do, because it keeps me excited and engaged and surprised.

"This is no exception but it was very odd sometimes to come from playing the mastermind of Brexit to this."

It is only now he is sitting down to discuss The Grinch that he is thinking about the significance Christmas films can have to young people, especially now he is the father of two young sons.

"That is something that is just dawning on me," he says.

"I thought this will be this season's go-to. But hopefully it will be one of those ones that will be on telly.

"I hope it does because there is a lot of very good work in it. I say that very humbly.

"You do voiceover artists' stuff in this and it's fantastic and very creative, and sometimes you get to shift the script a little bit and influence the way he sounds and that is fantastic, but the real work is the animation and it's just spell-binding.

"I just sat there going, 'Wow, this is amazing and nothing to do with me in it' - and I think it will last for a while."

The Grinch is in cinemas now.