Saoirse Ronan ''sobbed hysterically'' when she watched 'Lady Bird' for the first time.

The 23-year-old actress was ''so nervous'' about seeing her leading role in the coming-of-age drama and she thinks director Greta Gerwig has made a ''beautiful'' movie.

She said: ''I watched the film for the first time with my best friend in October. We had a couple of glasses of white wine before we went in because I was so nervous, but we had our arms wrapped around each other.

''Even though I knew what was going to happen in the film, I was laughing one moment and sobbing hysterically the next. It's about the beautiful struggle of being a teenager, growing and changing and getting to know yourself, and having the realisation that relationships change.''

And Saoirse admitted she identifies a lot with her titular character in the film.

Speaking to the director in conversation for the Sunday Times, she said: ''I identify with a lot in 'Lady Bird'. The great thing about how you've written the character is that she doesn't know how great or special she is. And there's a huge sense of the importance of belonging, belonging to a place, a time in your life.''

The award-winning actress admitted it was unusual for her to enjoy the finished film so much because she normally works on a project to hang out with ''brilliant'' people.

She said: ''The crew are the people I want to hang out with when I'm working, and that's why, usually, I actually don't get anything out of watching the final cut of a film. Most of the time, as cheesy as it sounds, I'm not doing a movie for that, I'm doing it because I get to work with these brilliant people. I think there's definitely an Irish thing in my head that tells me not to take up all the oxygen in the room, too.''