Lindsay Lohan has checked out of a Malibu rehab center after a stay of more than six weeks and will wear an alcohol-monitoring ankle bracelet.

The "Mean Girls" star, who turned 21 on July 2, left Promises Malibu Alcohol and Drug Rehab Treatment Facility on Friday, according to a report on People magazine's Web site Sunday.

She will voluntarily wear the bracelet as part of an intensive outpatient program, said her publicist, Leslie Sloane Zelnik, in a statement.

The alcohol-monitoring bracelet measures vapors from a person's skin for traces of ethanol, which the body makes when digesting alcohol. The results are then sent to a computer modem for data collection.

On Saturday, Lohan was reportedly seen partying at Pure Nightclub in Las Vegas with several friends.

"In part she is wearing the bracelet so there are no questions about her sobriety if she chooses to go dancing or dining in a place where alcohol is served," Zelnik said.

Lohan checked into the swank facility after a wild Memorial Day weekend during which she crashed her Mercedes Benz into a curb, was arrested on suspicion of driving under the influence and was photographed slumped in the passenger seat of a friend's car.

Her outpatient program includes going to Alcoholics Anonymous meetings, taking daily tests and receiving therapy.

"She's doing great," Zelnik said. "Lindsay is working hard on her sobriety and we are all supporting her."

It was the star's second stint in rehab this year. She said in January she had checked into a rehabilitation center for substance abuse treatment.