It’s barely one day into Sam Lufti’s defamation lawsuit against Britney Spears, his former employer, and the case has already taken a turn for the ugly.

In his opening testimony, Lufti’s lawyer dropped bombshell allegations that Spears was addicted to amphetamines while Lufti was her manager, and shaved her head during a paranoid episode because she was afraid of being drug tested.

Lufti, who served as Spears’ manager from 2007 to 2008, is suing Spears’ parents, Jamie and Lynne, for libel and breach of contract, claiming he was promised 15 percent of the star’s earnings but never received pay.

Joseph Schleimer, the attorney representing Lufti, said in his opening statements on Thursday, "My client was made a scapegoat for the drug abuse and erratic behavior of Britney Spears. She liked to use amphetamines—speed or uppers. She liked to take that drug. And most of the things that went wrong were related to that drug."

Schleimer also told the judge that in 2008, in the two days leading up to her involuntarily committal to a mental ward, Spears filled a prescription for 30 amphetamine pills and swallowed most of them before locking herself in a bathroom with one of her sons.

"On January 3, 2008, she'd been up all night, popping these pills for 36 hours, and when it was time to give up her kids [who were scheduled to see her ex-husband Kevin Federline, as per their custody agreement], she locked herself in the bathroom," said Schleimer.

Spears' camp has yet to respond to the drug allegations.

TMZ reported that Lufti’s current claims directly contradict statements he made about the singer in 2010. When a reporter asked Lufti about Spears’ infamous head shaving episode, Lufti defended the star, telling TMZ that he thought her decision was,"a cool thing ... somebody expressing their artistic side."

"I think she was just expressing her independence and her freedom,” continued Lufti. “There's nothing wrong with Britney.  She's awesome."