Britney Spears left rehab on Wednesday after spending only one day there, according to reports, just a week after she spent the same amount of time at a different facility.

The television news magazine "The Insider" initially reported that Spears called a car service, walked out of the Promises Residential Treatment Centers in Malibu, Calif., and left the facility early Wednesday morning — far short of the usual 45-day stay.

Later, the TV show "Extra" and the Web site TMZ.com said Spears, 25, had left the center.

The troubled pop star and mother of two tried to get into a tattoo parlor before going home, but it was closed, "Extra" reported.

Spears checked into rehab Tuesday after a bizarre weekend that included shaving her own head and getting new tattoos.

Photographs showed a bald Spears on the grounds of the rehab center, smoking a cigarette and wearing a punk-rock style pink tank top emblazoned with the word "delicious."

Spears' manager, Larry Rudolph, told People magazine's Web site that Spears had voluntarily checked herself into a treatment facility.

"We ask that the media respect her privacy as well as those of her family and friends at this time," Rudolph was quoted as saying.

Video: What are the legal issues surrounding Britney's kids?

Last week, Spears checked herself into Eric Clapton's Crossroads Centre rehab clinic on the Caribbean island of Antigua — but stayed only 24 hours.

Many speculated that the star was having a nervous breakdown or at least a public meltdown when she gave herself a buzz cut on Friday night.

A friend of Spears' soon-to-be ex-husband Kevin Federline told the New York Post that the one-time backup dancer and aspiring rapper had joined forces with Spears' mother to get help for the multiplatinum-selling pop singer.

"He has put his career on hold right now to focus on his kids and his family — to try and get Britney better," the pal said. "The girl has gone bonkers and everyone is shocked the kids were still in her care. But her mom, Kevin and her dad are all in L.A. right now trying to take care of her."

Late-night talk-show host Craig Ferguson decided not to poke fun at Spears Monday night, saying that after seeing photos of the pop star's shorn head, he reconsidered making jokes at her expense.

"We shouldn't be attacking the vulnerable," he said, adding that "she clearly needs help."

Spears' public divorce isn't helping matters, said New York-based psychiatrist Gail Saltz, who also suggested that Spears could be suffering from postpartum depression.

Others also weighed in.

"This girl is out of control," Joy Behar, a co-host on ABC's "The View," said Monday. "And, she's in a lot of trouble. A lot of people feel this is self-mutilation."

"She is a child star unraveling and is the perfect example of when a child star evolves into an adult and doesn't have someone telling them what to do, or giving them the right affirmative advice, and the right support," said Ian Drew, editor at large at Us Weekly magazine.

Wild Weekend

But spies say Spears seemed fine over the weekend.

Less than 24 hours after her act of "shear madness," Spears happily lounged poolside at West Hollywood's chic Mondrian hotel sporting a short blond wig and green cap to cover her skull.

Though rumors persisted that Spears had "lost it," witnesses at the pool said she seemed to be in good spirits, chatting with her friends and chain-smoking. Her kids were not with her.

"She was definitely having fun with her friends," said E! gossip columnist Marc Malkin.

Cameras also caught Spears sporting a platinum blond wig at The Roxy in West Hollywood Sunday night.

Video: Click here to see video of Britney wearing a wig

As for the buzz cut, a Las Vegas gossip Web site offers another possible reason for Spears' new do.

Three weeks ago, it says, Spears went to a salon in the Palms hotel and casino in Las Vegas. There, staffers found her hair was so badly damaged from repeated dye jobs, bleachings and extensions that it had broken off and thinned to the point "where bald spots had begun to appear," the site reported.

So she may have clipped it off to start over.

Spears also may have shaved off her hair in an act of rebellion against her mother, a source told the New York Post on Sunday.

The source, with the Los Angeles-based X17 Agency that shot photographs of Spears' haircut at a Los Angeles hair salon Friday night, said Spears and her mom, Lynne, 50, had been feuding over the mother's demand that her daughter clean up her act and settle into motherhood herself.

The source said Spears and her mother had been fighting about rehab since she returned to Los Angeles — and the photo agency has pictures to prove it.

So Spears shockingly shaved off her long locks to rebel against her mom, the source said.

Lynne, who lives in Kentwood, La., flew to Tinseltown last week to be with her daughter — and to help take care of Spears' kids, Sean Preston, 18 months, and Jayden James, 5 months.

"Yes, Lynne took a flight to see her a few days ago," Spears' cousin Ernest Spears told The Post Sunday.

Buzz Cut

Spears strode into Esther's Haircutting Studio in the Tarzana section of Los Angeles on Friday and asked owner Esther Tognozzi to shave her head.

"I tried to talk her out of it. I said, 'Are you sure you're not having a bad day and tomorrow you'll feel differently about it? Why don't we wait a little bit?'" Tognozzi told a cable news network.

"She said 'No, I absolutely want it shaved off now.' Next thing I know, she grabbed the buzzer and she went to the back of my salon and she was shaving off her own hair," Tognozzi said.

When she finished, she declared: "'Oh, my God, I shaved it all off. My mom is going to be upset with me.'"

Then as TV cameras rolled, shutterbugs snapped and onlookers cheered and jeered, Spears put a hood over her hairless head, got into her black SUV and was driven to the Body and Soul Tattoo parlor.

There, she had red-and-pink lips tattooed on her wrist and a black, white and pink cross inked on her lower hip.

Esther's Haircutting Studio has set up a Web site to auction off the hair and other items for a minimum price of $1 million, said J.T. Tognozzi, who owns the salon with his wife.

"This is it, the opportunity of a lifetime," according to BuyBritneysHair.com. The winning bidder gets Spears' dark, knotty hair extensions, the clipper she used to cut them off, the Red Bull she drank at the salon and her cigarette lighter.

Downward Spiral

Since filing for divorce from Federline in November after two years of marriage, Spears has drawn criticism for her drinking, partying and sloppy appearance — including a public display of her private parts and collapsing of "exhaustion" on New Year's Eve.

Recently, she was spotted vomiting on herself at a New York hotspot and partying in just a bra and a pair of panties.

Last week, Spears' former assistant Felicia Culotta posted a letter on a Web site's gossip blog saying the pop star was headed for "rock bottom" and adding that her friends and family members were trying to help her.

Spears' ex-boyfriend Justin Timberlake also may have relayed a secret message urging her to clean up her act.

While accepting an award for Best International Male Solo Artist at the Brit Awards last Wednesday, the 26-year-old said in his pre-recorded speech:

"Stop drinking! You know who you are. I'm speaking to you! You are going to get sloppy!" he said. "OK! Magazine is going to say something bad about you."

Timberlake's representative insisted he wasn't referring to Spears, "just people in the crowd, no one in particular."

But Spears' has been known for impulsive and strange antics even before the split from K-Fed. Last year, she was photographed driving at high speed in Los Angeles with her infant son placed dangerously on her lap in the driver's seat.

That was followed by a strange interview with NBC's Matt Lauer last summer, in which Spears repeatedly tugged at her poorly dyed blond hair and wept as her fake eyelashes dangled from her face.

In January 2004, she had her 55-hour Las Vegas marriage to childhood friend Jason Alexander annulled.

The Associated Press and the New York Post contributed to this report.

Click here to view photos of Spears cutting her own hair.

Click here to view video of Spears' new do and tattoos.

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