Colin Farrell took "five or six days off" after filming the thriller 'Killing of a Sacred Deer' because he felt down due to the movie's "bleak core".

Colin Farrell

Colin Farrell

The 41-year-old actor stars as surgeon Steven Murphy in the new psychological thriller by Yorgos Lanthimos and Farrell admits the role got to him and part of the problem was he couldn't escape his character when he wasn't on set because he had to grow a beard for the part.

Speaking to the Metro, Farrell said: "I do always hate talking about finding this work hard because of my Catholic guilt. I know I am fortunate. But, honest to God, by the end of this film I was down. Part of that was to do with the beard. Some people love beards, for sure, but it really weighed me down. But mostly it was the tone of the film. It's just bleak to its core.

"Yorgos thinks it's a comedy, that this is his 'Anchorman'. I beg to differ.

"By the end of the two weeks I was just ready to be done with it. On the night we wrapped, I shaved the beard off. That helped some.

"Then, rather than just go straight home and have to pretend to be happy and upbeat to my kids, I took five or six days off. I just did hikes and nature and things like that."

'The Killing of a Sacred Deer' follows the story of Steven Murphy and his family who has been accused of killing a patient on the operating table.

But he has to make a big sacrifice when the behaviour of a teenage boy, who he has taken under his wing, starts to turn sinister.

Farrell stars alongside Nicole Kidman, who portrays Steven's wife Anna, in the movie, and the Oscar winner recently admitted that it was one of the strangest films she has ever worked on.