08/12/2009 at 01:00 PM EDT
When it comes to shaping up Mischa Barton
is nothing but serious. Currently in New York City to shoot the TV show A Beautiful Life
, the actress has been hitting the downtown Equinox gym and even hiring a trainer.
"Mischa is really focused on getting into shape,” says a source with knowledge of the situation. Last month, the actress, 23, suffered a breakdown
and spent several days in a psychiatric ward after police were called to her home in Los Angeles.
The focus on fitness might be just what Barton needed. "She has big self-esteem issues," a source close to her told PEOPLE last month. "She hates her legs. She isn't comfortable with her body. It's been a big source of stress and self-hate."
Since relocating to New York City in late July, Barton has been trying to change that. "Mischa has been doing a lot of conditioning with weights as well as cardio on the treadmill, and some kickboxing," says a source. "She's been very consistent and she seems focused."