Colin Farrell is "fascinated with pain"

Speaking to Jessie Buckley for Variety's Actors on Actors series, he said: "I have mad moments of joy in my life and joy in work and joy with my kids.

"But I've always felt that the common denominator in regard to experience as humans is pain.

"The one thing we've all felt, really, is pain. I put fear and uncertainty under that banner.

"Not everyone, sadly, has felt joy. And that's a great tragedy.

"But I'm fascinated with pain. Every single act of aggression or violence has its root in pain that has become personalised."

Despite his own past struggles with addiction, Colin insisted he didn't draw on his own experiences for his latest role because he thinks it is such a "particular" thing to go through.

He said: "When I read 'Ballad', it was a character that .. there was no reason, no backstory given in the script - he just was somebody who was drowning beneath this agitated pain.

"I couldn't really figure it out when I read it. I concocted whatever fiction for myself in regard to backstory. But I just wanted to explore it.

"I've had a history of addiction and bits of depression and anxiety - the whole smorgasbord of human frailties as well.

"Inevitably, you're always drawing from your own personal experience, but I didn't feel like I was drawing from the experience I had with addiction, which was very particular.

"The addiction is just a consequence of certain things unanswered or certain uncertainties that are too fearful to even comprehend. So you pretend they're not there.

"And you pretend that you have answers when you don't have any business having an answer at that particular point. You just have to sit in the uncertainty of it all - sit with the agitation and the sorrow and the fear of that."

The Penguin star - whose eldest son has Angelman syndrome, a rare genetic disorder - knows his work is a "privilege" in the way it allows him to explore all his experiences and feelings, but he is also aware that it can't change his life in a significant way.

He said: "The permission to be overwhelmed is a huge thing to give to each other, to give to our kids.

"I'm so f****** aware of the amount of privilege that I've experienced in my life and what rare air I fly in regarding what I do for a living. But at the end of the f****** day, there's nothing I can do in acting that can make James, my oldest boy, talk or have language."