According to Entertainment Tonight, Spears checked out of the Promises rehab facility this morning after staying for less than 24 hours. No word yet on why she left this time, but it’s the second time she’s checked out of rehab in less than a week.

Spears’ manager Larry Rudolph issued a statement yesterday, saying: "Britney Spears has voluntarily checked herself into an undisclosed rehab facility today. We ask that the media respect her privacy as well as those of her family and friends at this time."

Though focus has been on Spears’ hard-partying ways since she filed for divorce from husband Kevin Federline late last year, friends are coming forward saying the 25-year-old pop singer has been battling substance abuse for some time.

According to In Touch Weekly, the sister of Britney’s first husband Jason Alexander, who she married in Vegas and later had the union annulled, says she’s seen the singer party when visiting her family back home in Louisiana.

"When I was around her, she took Ecstasy," 21-year-old Amanda Alexander tells the magazine, saying she’s also seen Spears use cocaine.

Another hometown friend, Kent Smith, who's says he’s known Britney for at least 10 years, tells the magazine the two partied together three years ago in New Orleans."She does like to party," Kent tells In Touch. "I've been there when she's done Ecstasy and cocaine."

Sources say that in the months since the split, Spears’ drug intake has increased. According to In Touch, they also have sources who says she smokes excessive amounts of pot, drinks heavily and uses prescription drugs including Xanax (for anxiety) and Paxil (an antidepressant).

Over the weekend, Spears seemed to be issuing a cry for help when she dropped into a barbershop in the San Fernando Valley and shaved off all of her hair. She was then spotted around town over the weekend wearing a platinum blonde wig, sunglasses and a string of pearls.

Stay tuned for further developments on Spears’ latest stint in rehab.

until next time!