The "Toxic" hitmaker is currently embroiled in a bitter battle with her ex-husband Kevin Federline over the care of their two sons, Sean Preston, 2, and 1-year-old Jayden James.
Spears' lawyer Laura Wasser quit on Monday with reports suggesting the attorney found the star a "problem client."
Melvin Goldsman was named as Wasser's replacement on Tuesday, but Spears is considering firing him, according to high-profile divorce lawyer Sorrell Trope.
Trope claims he has been chosen as Goldsman's replacement.
He tells People.com, "Yes, it's true Ms. Spears quit Melvin Goldsman's firm, but we haven't been officially retained yet.
"The paperwork has not been signed, and it has to have our firm's, Goldsman's, and Ms. Spears's signatures. I anticipate it will be signed on (Wednesday)."
Meanwhile, Federline is "happy" with the judge Scott Gordon's decision to order Spears to undergo twice-weekly random drug testing after he raised concern about the singer's apparent "habitual, frequent, and continuous use of controlled substances and alcohol."
Federline's attorney, Mark Vincent Kaplan tells People.com, "It would appear the court wanted to stabilize the status quo, but also implement orders that give as much protection to the kids until the court has the benefit of the...evaluations.
"Kevin is happy the case is moving forward in a positive direction."
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