Maggie Gyllenhaal can’t imagine letting her daughter, Ramona, 3, hang out unsupervised with an alcoholic vagabond musician.  But it’s what her character Jean does, with unexpected consequences, in Fox Searchlight’s new drama “Crazy Heart” for which she recently earned a Best Supporting Actress Oscar nomination.

“Being a mother forces me to be so responsible. I’m very protective, and I try to keep (Ramona) out of this Hollywood stuff,” says Gyllenhaal, 32. “But I make mistakes. I have that tug of wanting things that feel good to me and trying to figure out in what ways I have to sacrifice and what ways she has to sacrifice. I haven’t been perfect at that.”

Gyllenhaal, whose last major film role was in 2008 hit “The Dark Knight,” says she’s torn between her family life in Brooklyn, where she resides with her husband, Peter Sarsgaard, and Ramona, and the desire to work. It’s why she felt compelled to play novice reporter and single mom Jean in the drama, co-starring Jeff Bridges as a boozing country singer who meets Jean during an interview and ends up bedding her.

“When I got this script, I was in this state of wanting something for me, selfishly, after having sacrificed a lot of things,” Gyllenhaal says. “I felt really hungry — I felt like I’d spent two years mostly focused on my daughter, which was amazing. It changed everything in my life. And then I got this surge of really strong desire to do something for me. I couldn’t find a match. When this movie came, the size of it didn’t make any difference to me. I knew I had to do it.”

Jean, Gyllenhaal muses, “was having the same feelings. After four years of raising this kid basically by herself, I think she’s in an emergency state of where I was — just give me something for me, just a little something. She doesn’t care if it’s bad for her. He makes her feel like a woman.”

Bridges says that like Jean, Gyllenhaal is both fragile and ferocious. The two first met at the December 2003 Manhattan premiere of Gyllenhaal’s movie “Mona Lisa Smile,” where Bridges told the actress they’d work together someday.  “With Maggie, there’s a tenderness and sensitivity for herself and others. She’s very open and sweet, and then she has a tough side, too, that is protective of her tenderness,” Bridges says.

In person, Gyllenhaal used to be cool and somewhat standoffish. Today, she’s a different person: sweeter, gentler, gigglier and far more approachable. She attributes the change to growing up and becoming a mom.

In her 20s, Gyllenhaal says, “I thought the idea was to be as strong as you could in my work, in my life. To just be fierce and bold. I don’t think that anymore. I’ve gotten softer.  You have to be so brave to feel your feelings. You have to have a different kind of strength to reveal the ways in which you’re weak and the things you’re ashamed of. And I think Jean has more of that than anyone I’ve played.”

Distributed by Twentieth Century Fox through Warner Bros., “Crazy Heart” opens exclusively at Ayala Malls Cinemas – Glorietta 4, Greenbelt 3 and Trinoma – starting March 3