Keith Urban feels "disturbed" watching his wife Nicole Kidman on screen.

Nicole Kidman and Keith Urban

Nicole Kidman and Keith Urban

The 50-year-old country singer finds it hard to separate his spouse from her characters and found it incredibly touch watching her work opposite Colin Farrell in 'The Killing of a Sacred Deer', a horror film in which she plays the wife of a surgeon who has to make an unthinkable sacrifice.

Nicole, also 50, admitted: "[Keith] is an artist. Um, he did have a hard time when he watched 'The Killing of a Sacred Deer'. He saw it at the Cannes Film Festival and he was sort of hypnotised and shattered by it.

"And when he watched 'Big Little Lies' he was disturbed; he says that when he hears me scream or cry from a certain place in my soul it's almost like it goes straight into him and he has a visceral reaction immediately.

"Because his brain and his heart doesn't discern between acting and real life. They're the same sounds for him. It throws him."

The award-winning actress - who has daughters Sunday, nine, and Faith, seven, with Keith, as well as Isabella, 25, and Connor, 22, with ex-husband Tom Cruise - was also full of praise for Alexander Skarsgard, who played her violent on-screen husband in 'Big Little Lies', admitting they have a special "connection".

She told W magazine: "There were times on that set when it was intense.

"But he and I communicated. There had to be such safety and such honesty and such raw vulnerability there that we have a different connection."

In September, Nicole caused a stir when she kissed Alexander on the lips when he picked up the Outstanding Supporting Actor in a Limited Series or Movie award but she insists it was just a natural reaction "in the moment".

She explained: "I mean, I'd kissed him many, many times on the set.

"Much more than that. So that was just my way of going, in the moment - we were both shocked and we were like, 'Oh, my gosh, I'm so glad you won.'

"Because I know what he put into that role. And to see him standing up there and to hear his name read out was just, I mean, that was a really brave thing that he did, to play that person that way.

"He never pulled back and he never talked about, never worried about how he was being depicted. He was just very honest and very true to what the story needed."