A L.A. County Superior Court judge has signed a "5150," meaning Britney Spears is on a three-day psychiatric hold at the UCLA Medical Center.
There is a "good possibility" it will be extended to 14 days.
There have been several concurrent attempts to get Britney on a 5150. Spears' own lawyers, Anne Kiley and Tara Scott, secured a new psychiatrist for her late last week - and he's the one who triggered the 5150 last night.
At the same time, we're told Britney's mother, father and brother have been "working closely with the LAPD for weeks" to get her psychiatric care.
Meanwhile, a bitter fight is taking place over who is in control as far as making the troubled star's medical decisions.
Insiders say Britney's parents, Lynne and Jamie Spears, are currently not calling the shots in making medical decisions on behalf of Britney.
Right now, it appears Sam Lutfi is in the driver's seat.
Sources close to the case say that after Britney's stay at Cedars-Sinai January 3, she had her lawyers draft up paperwork making it clear she did not want her parents involved in making any medical decisions on her behalf.
Jamie Spears (above) reportedly went ballistic, screaming and swearing at Sam Lutfi - even pushing him physically - right in front of Britney.
As to what paperwork she signed, if any, that's unclear.
If Britney signed a durable power of attorney, that could give someone power to make medical decisions on her behalf in an emergency.
No such document was reportedly signed, but somehow Britney Spears made it clear she wanted Sam Lutfi - not her folks - to make decisions.
Right now, the doctors at UCLA are working with Osama, not Jamie and Lynne Spears. Lawyers are involved and a judge will have to sort it out.
More to come throughout the day. Follow the jump for more details on how Britney was hospitalized in the early hours of the morning ...TMZ reports that at some point last night, Britney's new psychiatrist went to her home and felt she was a danger to herself and others - partly because of her reckless driving and partly because of her "downhill behavior."
As a result, the shrink launched a (long-awaited) plan to have Britney Spears committed to UCLA Medical Center by calling the police.
The plan was for cops and paramedics to take Britney away the night before, but it was scrubbed. Last night, it all went down according to plan.
Cops even used code to minimize craziness in transporting Britney to the hospital. Over the police radio, she was referred to as "The Package."
Before the cops arrived, the psychiatrist told her she was going back to the hospital. She offered no resistance. She said, "Is something wrong?"
Meanwhile, Lynne Spears became agitated, accusing Sam Lutfi of engineering the impending commitment. Britney allegedly told Lynne to "shut the hell up." The singer demanded silence, sat on the floor and waited.
Emergency personnel arrived shortly thereafter, and Britney Spears was taken away on the gurney without resistance.