Cara Delevingne is "not an airhead model"

Recalling how Cara became involved with the movie, Nat told Teen Vogue magazine: "It was great being involved in the casting process, which, honestly, I hated it in the beginning because I hate auditioning. I know how awful it is for actors.

"Cara came in, and I was the only person in the entire world who hadn't heard of her. And then she blew me away.

"She's the only one who made me feel nervous, because she's such a spontaneous actress. People think, She's so hot and so rich - how can she be talented? She's not an airhead model. She is so talented."

Meanwhile, Cara confessed recently she started acting because modelling made her feel "empty".

The London-born star - who has already appeared in 'Anna Karenina' and 'The Face of an Angel' - said: "I ended up feeling a bit empty.

"Fashion is about what's on the outside, and that's it. There's no searching, it's just creating pretty things."