Actress Vera Farmiga, known for her work in The Departed and The Boy in the Striped Pyjamas, stars opposite George Clooney and Anna Kendrick in Up in the Air. She was recently in London, where she talked about Up in the Air, working for an air condition company, filming nude scenes and being mistaken for a film producer.

It's a joyful script to listen to. It must have been a pleasure for you to read. How did you assess your character when you first read the script? Alex is a similarly free-spirited character, but of course with hidden depths that we discover later.

Vera Farmiga (VF): Yeah. I didn't have the luxury of reading the script without knowing what happens in the end, so I had preconceived ideas. And it was challenging to play a woman who was very much like a man. And oftentimes, when a woman behaves this way, it can be interpreted as – it was difficult for me to – it was a fine line, I found, to tread, to have the softness and yet to sort of take control of her sexuality and unapologetically make demands that usually you see men making in scripts. And I really liked the male perspective on heartbreak that I hadn't read before.

Obviously, unemployment features quite heavily in the film. Do you have any interesting experiences of being fired?
VF: I worked as an air-conditioning technician for Fedders & Emerson Fine Cool Air Conditioning, as a customer service representative, who repaired air conditioners over the phone, as much as I was able to tell them whether the VTU was too large a unit for the space they were trying to cool or whatever. And I guess I was too chatty on the phone. I didn't get fired, but they did want to demote me, take me off the phones and give me more of a clerical position, but I just shortened the chat.

There were lots of real life locations used in the film. Did that present any particular challenges?
VF: What was most amusing for me was to see the fanaticism that George attracts. I mean, that was overwhelming and so odd. For me, no one ever knows who I am, they always think I'm a producer on the film, but watching George having to deal with that, and him having just to simply open a door and close it and then there's a standing ovation that goes for blocks! And he's so gallant and gracious and takes his bow. But I didn't think that it impeded any of the work.

In the nude scene, was that really you? And if it was, how comfortable were you with it?
VF: I had shot this when I had about six pounds more trunk in my badunk-adunk. I was pregnant and I did do the scene. But I think my bottom had become too large (laughs). I didn't think so – I think that's a question for Mr Reitman, because I did attempt to do the nudity. I got to certainly choose my body double and I thought Jason did a good job of selecting someone that was pretty accurate – my body double, Trish has been in many films. Perhaps on the DVD extras...