Benedict Cumberbatch has said he kept his work and home life separate when he filmed his new role as a father who loses a child, as taking it home with him would have been “incredibly unhealthy”.

The Sherlock star – who has two young children with his wife Sophie Hunter – plays author Stephen Lewis in the BBC One adaptation of Ian McEwan’s award-winning novel The Child In Time.

The book follows Lewis and his wife Julie (Kelly Macdonald) as they struggle with the loss of their four-year-old daughter.

Cumberbatch, 41, said: “I don’t think I did (take the work 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.

“It’s incredibly unhealthy to bring work home, so I think in general I would have avoided that.

“I 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 try to separate the two things in this instance.”

Cumberbatch and theatre director Hunter are parents to two-year-old Christopher and welcomed a second son in March this year.

The actor said The Child In Time was a harrowing shoot, partly because the situation Lewis finds himself in was “kind of unthinkable for any parent”.

He said: “It’s hard sometimes, because you’re running that all the way through the day and there are many beats in the story.

“I mean, when you have the chance, which is not always the case in television, to do more than a couple of takes, you want to give as much variation as possible so there are lots of moments where those cracks appear, manifest, and then it’s a matter of how much can an audience take?

“But 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.”

:: The Child In Time is on BBC One on Sunday September 24.