In the movie, written and directed by Andrea Arnold – who is known for exploring themes of class in her work, the Bafta-winning star plays single father Bug, who lives in a squat in north Kent.
Keoghan, 31, grew up in a working-class area of inner-city Dublin and, as a child, he was placed in a dozen foster homes along with his brother.
His mother died when he was around 12 years old, at which point he was living with his grandmother.
German actor and dancer Franz Rogowski and Irish actor Barry Keoghan (Doug Peters/PA)
Speaking at a press conference on Friday, the Saltburn star said: “Growing up in Summerhill – there’s a lot of similarities in the working class.
“I’ve seen a lot of traits in Bug that reminds me of lads back home and there’s a lot of similarities that I could pull from.”
The movie, also starring Bafta TV winner Jasmine Jobson, premiered at the 2024 Cannes Film Festival in France on Thursday.
Keoghan also responded to a question about dancing in front of the camera.
At the end of Emerald Fennell’s film Saltburn the actor famously danced naked around a manor to the song Murder On The Dancefloor by Sophie Ellis-Bextor.
“I don’t think I can dance though, honestly, I think I’m a bad dancer,” he said.
Jason Buda, Nykiya Adams, Franz Rogowski and Barry Keoghan during a photocall for the film Bird during the 77th Cannes Film Festival (Doug Peters/PA)
“But I think the beauty of dancing on screen is the effort of trying.
“Seeing someone try to dance is very attractive and intriguing for me.
“Music plays a big part in everything I do and I know Andrea is big on music as well.
“When you go in and you kind of immerse yourself in the character, you want to surround yourself with a playlist or there’s been some characters that I have played that don’t listen to music weirdly.
“It’s a big part of developing the character.”
Keoghan has also been in Dunkirk, The Banshees Of Inisherin, The Killing Of A Sacred Deer, Top Boy and war drama series Masters Of The Air.
