Britney Spears is scheduled for a deposition in Los Angeles next Monday in connection with a lawsuit brought against her by the man who claims to have been her manager, Sam Lutfi.

Lutfi is suing Spears for breach of contract, among other things. While the case originally went to trial in 2012, a source close to the case tells ET why Spears was not allowed to be deposed until now.

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"Britney is in a conservatorship and the probate court which handles those originally said that Ms. Spears cannot be deposed or testify," our source explains. "The trial court judge in this case essentially went along with that original ruling. When Sam lost the trial, he appealed, and one of the conditions of his appeal was that Ms. Spears should have testified and the trial judge made that ruling in error. The appellate court ruled in Sam's favor. That is why now that this case has come around for a retrial, there is no argument that she will be deposed."

While Spears has appeared healthy and happy as of late, 10 years ago she hit a downward spiral that dominated tabloid headlines. Court papers surrounding the Lutfi case reveal just how dark her descent became.

The papers claim that the singer was "struggling with drug abuse" and at one point spent a night in a parking lot.

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Fans will recall that in 2007, Spears was photographed shaving her own head at a Tarzana, Los Angeles, hair salon.

She was first placed under a temporary conservatorship in February of 2008, one month after a high-profile breakdown landed the then-26-year-old in an involuntary psychiatric hold (or "5150 hold," as it's also known) at the Ronald Reagan UCLA Medical Center. Eight months later, her father, Jamie Spears, and lawyer Andrew Wallet, became her official, full-time co-conservators. It was at this point that the singer's life seemed to move back on track.

In 2014, Spears shared with ET her positive outlook.

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"My main thing is to enjoy life and take one day at a time," she said.

Now, Spears is on top of the world again, making nearly half a million dollars per show with her Las Vegas residency, which is a "dry show," according to a source close to the Vegas tour.

"Everyone around her must be sober and no one can have a drink around Britney or bring alcoholic drinks backstage," the source said.

As for her upcoming deposition, the court confirmed that Lutfi is allowed to be in the deposition room but entry and exit must be at staggered times for Lutfi and Spears, and Lutfi is allowed no contact with Spears.