Brendan Gleeson has admitted that he found it difficult to switch between normal life and the harrowed, good natures priest he portrays in the critically acclaimed Calvary.

CalvaryBrendan Gleeson and Kelly Rielly star in 'Calvary'

A good priest in a small town populated by people with dark thoughts, James Lavelle’s life is threatened during a confession. Of course, they’re anonymous things, confessions, and he spends what he believes to be the rest of his living days attempting to narrow down his would-be murderer. 

"I found increasingly the more I went into this thing, the more I needed to stay in there," he explained. There was one scene in particular that portrayed how the role continued to torment him even after director John Michael McDonagh yelled cut. 

"It was odd, at one stage John (Michael McDonagh, the director) told Aidan Gillen to call me a name when I was coming out of the loo after I find him snorting cocaine and there's no judgment, I just walk straight back out,” he said. 

"But I heard Aidan say something [insulting] at the end and it was the end of a Friday, the third week, and I was almost going back in through the door to say, 'Say that again,” continued Gleeson. 

"I was so sick of people freeloading and it has to seep into it. I'm not a method actor, but it was kind of relentless and I began to get really fed up of it."

Watch the trailer for Calvary here

He added: "Lines were blurred a bit, but it was a Friday evening and I think mentally I just switched off a little bit and crossed the worlds."

It seems, though, that the pain and effort was worth it. ‘Calvary’ has been reviewed excellently, accumulating an impressive score of 91% on Rotten Tomatoes.