Vanessa Hudgens on the set of Gimme Shelter
Sharpshooter Images/Splash News Online
01/23/2014 at 12:00 PM EST
Before playing a homeless, pregnant teen
in her new movie Gimme Shelter
, Vanessa Hudgens
paid a visit to Cannes – and she credits French cuisine with helping her pack on the pounds to look right for her role.
In particular, she thanks croissants.
"Oh my gosh, it was the easiest and most amazing thing ever," she told reporters at the film's Cinema Society and Alice & Olivia screening in New York City Wednesday. (the film opens Friday.)
"It's not hard to put on weight in France when you're eating all the good French food."
, which also stars Rosario Dawson
and Brendan Fraser, follows Hudgens's character as she flees the foster care system and her prostitute mother before she winds up in a Christian shelter.
The former Disney starlet
, 25, researched her role by visiting homes for at-risk teens. At the premiere, Hudgens called the experience "amazing."
"I would just spend as much time as I could with the girls," she said. "I didn't want to be too intrusive, and then I would just sit outside and work on my script. … It was just so nice because I knew I could bounce things off them."
Reporting by HAIWEN LU