Britney Spears' new lawyer is already 'aggressively' working to get her dad ousted from her conservatorship

• Britney Spears has new legal representation after her July 14 hearing at an LA courthouse.
• Mathew Rosengart told reporters he's "moving aggressively and expeditiously" to remove Jamie Spears.
• Rosengart's firm will petition to oust Jamie from the conservatorship "unless he resigns first."

Last week, Britney Spears' request to handpick her own lawyer was granted by the Los Angeles court, and Mathew Rosengart took over as her legal counsel in her ongoing conservatorship case. Now, Rosengart is making it clear that the first order of business for his firm will be petitioning to remove Jamie (Spears' father) from her conservatorship.

"My firm and I are moving aggressively and expeditiously to file a petition to remove Jamie Spears unless he resigns first," Rosengart said on Monday evening, according to Vulture legal correspondent Claudia Rosenbaum.

"I thanked Britney Spears for her courage and her strength," he said. "I thanked Judge Penny for her courtesy and welcoming my firm and I into the case. I also want to thank Britney Spears fans for their outrage. Their support for my firm, myself, and most importantly Britney has truly been overwhelming, coast to coast, and literally throughout the world."

During last week's hearing, Spears briefly spoke over the phone and said she not only wanted Jamie removed from the legal guardianship, but that he should be "charged with conservatorship abuse." At the same hearing, Judge Penny granted a request from Bessemer Trust to resign as coconservator of her financial estate, temporarily leaving Jamie as the sole assigned overseer of her estate.

A separate coconservator, Jodi Montgomery, is currently in charge of the part of the guardianship that oversees Spears' personal matters.

Insider reporter Azmi Haroun was present for last Wednesday's hearing, where Spears repeatedly expressed that she wanted Montgomery to remain as coconservator. But the pop star said she wanted Jamie removed as soon as possible.

"Spears grew emotional and broke down crying as she detailed her experiences with her father as a conservator," Haroun reported. "Spears said the conservatorship had allowed her father 'to ruin her life' and that she was frequently worried about him being inebriated."

The next scheduled hearing will take place on September 29 at 1:30 p.m. PT.

You can read more about the potential avenues Spears might use to oust her father from the conservatorship in our report here.