He’s enjoyed a meteoric rise to fame in recent years, but whether it’s a Hollywood blockbuster or TV drama, Benedict Cumberbatch tells Gemma Dunn he keeps work and family life separate

What isn't Benedict Cumberbatch working on at the moment? Since earning his breakthrough playing physicist Stephen Hawking in the 2004 TV film Hawking, the actor hasn't stopped - whether it be treading the boards as Hamlet, heading up hit BBC drama Sherlock or landing an Oscar nomination for his turn as mathematician Alan Turing in The Imitation Game.

In fact one glance at the 41-year-old's schedule - Gypsy Boy, The Jungle Book and How The Grinch Stole Christmas make up just a few of his upcoming projects - is enough to trigger a sweat.

I'm not surprised, then, to find Cumberbatch exhausted when we meet. "I'm a bit all over the shop with three hours sleep," he offers up, apologetically. "There might be moments where I just sort of stare vacantly out of the window..."

This time his lack of shut eye is due to the fact he's just flown in from LA, having attended Disney's glitzy D23 Expo in aid of the Marvel Cinematic Universe's 10th anniversary.

"It was great fun. It was one of those moments when you have to kind of pinch yourself," reveals the star, who joined the global franchise as Doctor Strange last year. "There was a lot of very, very experienced brilliant actors on stage, but all of us were just punch drunk by the enormity and the emotion of it. It's interesting because I think a lot of us don't necessarily gravitate towards that kind of work, but the lure of these jobs is they're fantastic. And then to look back and go, 'My God, this is the apex of 10 years' worth of work...' I'm not a numbers guy, but I was really blown away by it."

But while he will reprise his role as the Sorcerer Supreme in 2018's Avengers Infinity War, it's not all Hollywood blockbusters for the London-born talent.

Excitingly his latest outing is for the BBC (fans will be likely waiting a long time for a fifth season of Sherlock) and it comes in the form of chilling drama, The Child In Time. Based on Ian McEwan's prize-winning 1987 novel of the same name, the heartbreaking tale is the story of successful author Stephen Lewis (Cumberbatch), who is confronted with the unthinkable when his child is abducted in a supermarket.

As the scarring moment replays in the years that follow, the 90-minute film - the first feature to be made under Cumberbatch's production company, SunnyMarch TV - explores a marriage devastated by the loss of a child and the struggle and longing for hope that stems from all-consuming grief.

"It's about how two people who had each other before their love was manifest in a child break apart and come together again when they realise that they have to accept their circumstance," he explains of his character's relationship with on-screen wife Julie (played by Trainspotting star Kelly Macdonald). And never be in denial of it, never forget it, but also live a life and move on."

It was just the role Cumberbatch - a self-confessed 'huge McEwan nut' - had been looking for.

"I knew I wanted to play Stephen," he declares, having previously starred as Paul Marshall in Joe Wright's adaptation of McEwan's 2001 novel Atonement. "I had a desire to portray someone closer to me, someone who didn't acquire a few hours in make up or a great deal of strenuous - I wouldn't say mask work - but just something transformative.

Add such intimacy to the emotional and psychological toll that comes with portraying such a tragic subject matter, and "for an actor, for anyone, to imagine those circumstances is pretty harrowing", says Cumberbatch. "You want to give as much emotional veracity and truth as possible to those situations. They're kind of unthinkable for any parent; they're unthinkable for anyone who has children in their life, whether it's a brother or a sister or a son or a daughter.

"It's a horrific circumstance and it's very, very upsetting. So yeah, it was tough," he concedes. "But it's a sort of extraordinary thing to explore and I guess the way you deal with that, is you move out of it safely and try to have a moment of humour.

"It's hard sometimes though," he adds. "There was a point when I was worried I was getting a bit too upset in all of these scenes, which is hard to avoid."

Does such a powerful storyline hold more resonance now he's a father?

"Not really, no, I think that's just circumstantial," says Cumberbatch, who has two young sons with his theatre and opera director wife, Sophie Hunter. "I suppose it's easier to imagine, but it isn't that difficult to imagine. I certainly try to separate my own inner life from my character's inner life. But of course it's going to affect a parent, reading it, and watching it."

That said, he's clear on one thing: he does his utmost to never take a role home.

"I mean, the joy of returning home to the family is what that is, and if you're portraying something other in your work, then the divide is very, very simple," he says. "It's incredibly unhealthy to bring work home, so I think in general I would have avoided that. And didn't want to bring that subject matter even into our family life, so Sophie didn't read the script and she hasn't read the book. So that's, I suppose, an example of how I tried to separate the two things in this instance."

  • The Child In Time will air on BBC One on Sunday September 24