Lufti and the pop star have been embroiled in an ongoing legal battle for years, and a judge previously dismissed his allegations of breach of contract, libel and battery in 2012.

However, Lufti appealed the ruling and now the case has come back for retrial.

A source tells Entertainment Tonight, "Britney is in a conservatorship and the probate court which handles those originally said that Ms. Spears cannot be deposed or testify. 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 favour. That is why this case has come around for a retrial; there is no argument that she will be deposed."

Spears' legal team has reportedly filed a motion to keep Lutfi out of the room during the deposition in Los Angeles, and the documents they've handed over to support their argument features the 2015 decision by a panel of appeals court judges, which details Britney's mental health struggles in 2007 and 2008, when Lutfi was her manager.

According to legal papers obtained by TMZ.com, the judges declared the singer's life was in a mess when she met Lufti in 2007, explaining she was divorcing ex-husband Kevin Federline, fighting for custody of their kids, and "struggling with drug abuse".

Lufti reportedly urged Spears to get clean, but members of the star's family claims he wasn't helping her.

Sam insisted he only agreed to manage her if she stopped abusing drugs, but she continued to get high.

Apparently, Britney's problems got so bad she started sleeping in a parking lot on the day she lost custody of her two sons.

Her erratic behaviour led to a stint in a psychiatric ward as her her father, Jamie, took over her legal and financial affairs after winning conservatorship.

He managed to get Britney the personal and professional help she needed to get her life and career on the right track. Britney now fronts a successful Las Vegas residency and regularly spends time with her sons Sean Preston, 10, and Jayden James, nine.