Like her character in the film, Saoirse's parents moved from Ireland to New York in the 1980s, and she was born in the Bronx in 1994. "I was 3 and a half when we moved back, so this movie is really my mother and father's story," she says. "They struggled and it was hard. There were times they were doing well with work, and there were times they were broke."

Saoirse Ronan plays Eilis in the film BrooklynSaoirse Ronan plays Eilis in the film Brooklyn

Brooklyn is set in the early 1950s, and Saoirse enjoyed reconnecting to New York while she made the movie. "I loved the spirit and energy of the place," she says. "If you're coming from a small town in Ireland and you were never exposed to American people and American culture, it can be absolutely terrifying. Last year I moved away to London, and I went through that experience of my character. I was excited but also I felt very scared about the new experience, after being away from the security of home and my parents."

The film explores how tricky it can be to work out where your real home is. "It's a huge thing to know where your place is in the world," she says. "Homesickness is awful and everyone hates it, but eventually it'll pass, though you don't know when. It's just one of those stories I think that hopefully everyone can tap into. Everyone has their own immigrant story."

Brooklyn is Ronan's first properly adult role, and she's happy to be leaving her on-screen childhood behind. "I'm excited to be moving on to the next stage," she says. "I think this film was a great way to start that next moment, a transition to playing a young woman who has so many experiences that turns her into the woman that she is and gives her the life she has. That's a very grown up thing. I've been working since I was 10. I played a kid when I was a kid, and now I'm ready to move on.

Watch the trailer for Brooklyn here: