London, Aug 13 - Troubled actress Mischa Barton has embarked on a health regime and has hired a personal trainer to help her get fit.

The 23-year-old who was placed under involuntary psychiatric hold at Los Angeles' Cedars-Sinai Medical Center last month for mysterious reasons, is trying to turn her life around by training hard and embarking on a healthy lifestyle, reports tmz.com.

'Mischa is really focused on getting into shape,' said a source close to Barton.

'She has been doing a lot of conditioning with weights as well as cardio on the treadmill, and some kickboxing. She's been very consistent,' the source added.

Since returning from the medical centre and resuming shooting for her new show 'The Beautiful Life', Barton is concentrating hard on keeping fit, and is regularly spotted at her local Equinox sports centre.

Despite her new regime and positive outlook, friends of the troubled starlet fear she has returned to work too soon after leaving hospital.

'There still are issues. Mischa's just not herself at all. I think she's gone back to work too soon,' said a friend.