AceShowbiz - "American Animals" star Barry Keoghan once feared his difficult youth meant he'd be banned from his own film premieres.

The actor, who was born in Dublin, Ireland but plays a Kentucky college student in Bart Layton's new real-life crime drama, had a troubled childhood in the city.

Barry and his pals used to sneak into the Light House Cinema, behaviour that got them barred from the venue - something that caused him concern when his early movies "'71" and "Mammal" both debuted there.

"We used to sneak in, run upstairs, get chased. All that 'young kid' kind of thing," he recalled to The Guardian. "I was thinking, 'What happens if I go to this premiere and I'm still barred? Would they let me in?'"

Happily, the ban had been lifted, and he even hosted a Q&A screening of "American Animals" there in July.

Barry's mother died of a heroin overdose while he was still young and he spent much of his youth being moved between foster homes until his grandmother took him in.

"Foster care was a big part of my life," the 25-year-old explained. "My mother dying of drugs is not easy for any kid. Anyone dying is not easy, but certainly not a mother. Me and my brother, we stuck together."

The "Dunkirk" star took up acting at 17 and has now been taken under the wing of his "Killing of a Sacred Deer" co-star Colin Farrell - who himself has struggled with addiction problems.

"He's had his battles," Barry said of his relationship with Colin. "And that's why I really look up to him. He gave me a lot of advice. When you're chatting with him, he's genuine. It's a hard thing to find in people. To sit and just be present with someone, even for two minutes. Colin has that."

"American Animals" debuts in U.K. cinemas on Friday, September 07.