Lea Michele has offered her support to Zac Efron following his recent rehab stint.

The Glee actress - whose boyfriend Cory Monteith died from a heroin and alcohol overdose in July - has reached out to her New Year's Eve co-star following revelations he has been battling cocaine addiction and has vowed to do her best to help him stay sober. "Lea called Zac and told him, 'I'm here if you need me.' She urged him to get serious about having a 24-hour sobriety coach and to only spend time with people who care about his welfare. Lea must feel sad that she wasn't able to prevent Cory from relapsing. She knows Zac well and would hate to see him go down the same path," a source said.

Zac was delighted to hear from his friend and has promised to stay in regular contact with her. "Zac was really glad to hear from her. They have plans to go on a yoga outing together in LA later this year and he promised to discuss his state of mind with her weekly by phone or email," the source added.