Lily Collins has both Jewish and Christian ancestry, but appears to be non-religious.
She has nice things to say about Obama and is probably a Democrat.
Lily Collins was born in Guildford, Surrey, England and grew up there and in Los Angeles, California.
Collins doesn't talk about religion much, so I think it's safe to say she's fairly non-religious. She did send her "thoughts and prayers" out to victims of the Japanese earthquake and tsunami in 2011, but that could have been more a figure of speech than a religious sentiment. But it's probably also an indication that she's not an atheist.
I found one picture of her wearing a large cross –but only that one. It's very possible that the fashion choice was that of the photographer and not the actress.
Ethnically, Collins has some Jewish ancestry. Her maternal grandfather was Jewish but her maternal grandmother was not. Apparently the blood line of the latter relative can be traced back to a Protestant minister, but I digress. No matter what her ancestry indicates, she's still most likely not religious.
A Brit in America's Clothing
Collins doesn't consider herself a very political person, but it didn't stop her from reporting on the 2009 inauguration of Barack Obama in Washington, D.C. for the kids' TV station, Nickelodeon. She said about the experience,
I am not politically savvy but to be reporting on the election and the inauguration on Nickelodeon was a real joy. . . . I'm a fan of what he brought to the youth of America.
I wouldn't exactly call that an endorsement, but she appears to like him all the same. Maybe she's not all that interested in American politics because she considers herself more of a Brit. Even though she moved to the States when she was a young girl, she says, "Whenever I go back to England I say I am going home." But. . . she doesn't have anything to say about British politics either as far as I could tell.
So if I had to guess, I'd say she's liberal and votes with the Democrats–and maybe with Labour as well. After all, she is a Hollywood starlet.