Vanessa Hudgens transforms for 'Gimme Shelter'

• Hudgens stars in %27Gimme Shelter%2C%27 out Jan. 24
• The star cut her hair%2C put on weight%2C and lived in a homeless shelter to prep for the role
• After shooting wrapped%2C Hudgens had to %22work on loving myself again%22

WASHINGTON - "Just breathe deeply."

That's one of Vanessa Hudgens' New Year's resolutions. The star, 25, has it written in her journal as a reminder to be present, grounded and "in my body"—that's a phrase she uses often—and "connected to my soul."

While touring the country to promote her new drama Gimme Shelter, in which she stars as real-life homeless and pregnant teenager Apple, she's determined to keep her resolution. Even when paparazzi document her every outfit change and catch her sharing an intimate moment with her boyfriend, Austin Butler, outside of her Venice, Calif. acting class, Hudgens just breathes..

Being in the public eye is nothing new for Hudgens who rose to fame as Gabriella in Disney's High School Musical films. As a star, "your privacy is not respected… (but) I've always felt that I'm gonna live my life," she says.

When Hudgens read the script for Gimme Shelter (in theaters Friday), she had just gone through a breakup and "was finding myself (and) toying with the idea of spirituality," she says, noting that the role was "exactly what I needed."

She even shared some similarities with the character on a metaphysical level. "Apple goes through a metamorphosis, and I had just gotten my butterfly tattoo. It just really hit home," she says.

Hudgens committed to the movie "full-force" both physically and mentally. To immerse herself in the life of a teen mother, she spent time at Several Sources Shelter in Ramsey, N.J. getting to know the women living there and incorporating some of their mannerisms into her character. She also cut her long hair before filming, to "set the tone" for her character, whose short tresses are the result of a hair-chopping act of defiance. To make the transformation complete, she gained fifteen pounds to pass off as pregnant for a majority of the film's 2-hour run time.

While filming the movie, Hudgens experienced plenty of extremes. She popped blood vessels in her neck, the result of strenuous pushing in a labor scene. She ate out of a trash can to show the homeless Apple's desperate hunger. She hysterically yelled at a kind chaplain, played by James Earl Jones, from a hospital bed. ("His voice is so good. I want him to read me bedtime stories," she says.) She had on-screen screaming matches with her drug-addled mother, played by a yellow-toothed Rosario Dawson.

The intensity transferred over to her real life. While filming, Hudgens wasn't singing or listening to music. "I feel that when you go through dark times, the music of your life is dull," says Hudgens. "It was kind of a muted outlook."

Today, Hudgens looks flawless, fit and sophisticated in stilettos, a clingy skirt and loose updo. She's self aware, confident and keeps unblinking eye contact. She makes music ("a fun side project situation that's just for Vanessa"), she's been taking acting workshops and feeling connected to her religion.

But back then, she felt lost. She was portraying a character with "a lot of anger inside of her that all stems from fear and pain." And Hudgens says that pain didn't go away when the movie was over.

Hudgens felt "so meek and so scared and so disconnected" right after shooting wrapped, she says, her eyes moist with the memory. "I had to work on loving myself again," and just "connecting to my soul and body."

Hudgens' best friendhelped her out of the funk, and so did yoga. "I went on a yoga retreat, and it brought me back to life," she says, and back to work.

So where does one go after being the lead in a Disney franchise (Musical), starring in a comic book film (Sucker Punch), having an on-screen three-some with James Franco (Spring Breakers) and playing an abused, pregnant teenager? Her first comedy.

Hudgens' next project, coming out in October, is Kitchen Sink, co-starring Gossip Girl's Ed Westwick and Breaking Bad's Bob Odenkirk. It's "Shaun of the Dead meets Breakfast Club in a really crazy way,"she says, .

And after that, she'll see which character she connects with. Maybe she'll try a dark fantasy.

"I love pushing boundaries and challenging myself. I love the idea of transformation and being a chameleon," she says.