How Jessica Chastain's Nose Landed 'Mama' Role

Jessica Chastain is Hollywood's "It Girl" right now, with an Oscar nomination for her role in Zero Dark Thirty and this weekend's release of the horror thriller Mama fueling her forward momentum. Jessica trades in her ruby-red locks for a pitch-black punk look for her role as a musician in the movie, but she tells ET that it was actually her nose that landed her the coveted role!

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Jessica explains that when she was first cast, she wanted to know specifically why director Andy Muschietti chose her as opposed to her being forced on him by studio execs. With a hearty laugh, she says he replied, "I want to film your nose. … I love your nose. I want to film your nose."

Executive-produced by horror master Guillermo del Toro, Mama stars Jessica and Game of Thrones actor Nikolaj Coster-Waldau as Annabel and Lucas, a couple who unexpectedly take in a pair of girls (Megan Charpentier and Isabelle Nelisse) discovered in the wild. The feral pair were abandoned as babies in the woods the day their parents were killed, and miraculously, mysteriously survived for five years. When they are finally rescued and try to adjust to a brand-new life with their uncle Lucas and Annabel, it appears that someone -- or something -- still wants to come tuck them in at night.

Video: Jessica Reveals Dark Secrets of 'Mama' 

"A mother's love is very powerful," says Jessica. "You hear of mothers lifting cars off of their children; that's incredible strength – I don't know where that comes from in a person. But then you also know that they say the most dangerous animals are the mothers protecting their cubs. ... If a ghost is an emotion stopped in time, what happens if you take that emotion of a mother protecting her child and make a ghost out of that? That actually then becomes a very scary mother."