LOS ANGELES - After nearly a month of seclusion in a luxurious rehabilitation center, Britney Spears has moved on.

The pop star checked out of Promises Malibu Alcohol and Drug Rehab Treatment Facility "after successfully completing their program," Spears' manager, Larry Rudolph, said in a statement released by Jive Records late Tuesday.

He asked that Spears' privacy be respected.

Spears, 25, entered the facility Feb. 22 after a bout of bizarre behavior that included shaving her head, getting tiny lips tattooed on her wrist and beating a car with an umbrella. Photos of the incidents were beamed worldwide.

Spears' activities have been steady fodder for weekly magazines and entertainment Web sites since she filed for divorce from aspiring rapper Kevin Federline in November, citing irreconcilable differences.

Under a temporary agreement, the two have joint custody of their sons, Jayden James, 6 months, and Sean Preston, 18 months. Federline and the children reportedly visited Spears during her treatment.

Federline, who released his debut album in November, was celebrating his 29th birthday with his family Wednesday and then traveling to Las Vegas for a party Saturday at Pure Nightclub, said Federline's publicist, Marilyn Lopez. He originally had made plans for another bash Wednesday night in West Hollywood, but canceled that event.

"He just wanted to have one party instead of two and wanted to spend his actual birthday … with his family," Lopez said.

She declined to say if Federline was planning to see Spears on Wednesday.

Spears hasn't disclosed why she sought treatment at Promises, which offers detox, counseling and 12-step programs. A 30-day stay at the Mediterranean-style villa tucked in the Santa Monica Mountains costs $48,000.

With her stay there, Spears joined a long list of celebrities who have trekked to the facility to overcome addictions. Promises alumni include Ben Affleck, Charlie Sheen, Diana Ross and Matthew Perry.