The actress was desperate to be cast as Fiona Gallagher in the U.S. adaptation of the British show, about a dysfunctional family living in Chicago, Illinois, but producers felt she wasn't right for the role.
She tells Manhattan magazine, ""They didn't want to see me; they wouldn't even (let me) audition. They thought my image was too glamorous, that I couldn't not be pretty.""
Rossum shot a home video of herself as Fiona to prove she could handle the part, and she managed to land the job after three more auditions.
The 26 year old insists that in real life she is not at all like her promiscuous character, adding, ""Fiona is very sexually liberated. She's also a loudmouth, and there's safety in that. But I'm not the sex-on-the-first-date kind of girl.""