Entertainer Marie Osmond arrives at the 14th annual Andre Agassi Charitable Foundation's Grand Slam for Children benefit concert at the Wynn Las Vegas September 26, 2009 in Las Vegas, Nevada. (Ethan Miller, Getty Images)

Marie Osmond is embroiled in a court battle with a former manager who is demanding $88,000 in commission after she sacked him.

Osmond's legal team claims P. Karl Engemann, who managed the star for 35 years, was dismissed on October 23 for allegedly acting "in an inappropriate, improper manner and breaching his fiduciary duty to Marie."

But Engemann, whose daughter Shawn is married to TV host Larry King, has hit back with a lawsuit alleging he helped set up her lucrative Las Vegas shows with her brother Donny.

Engemann filed a demand for arbitration on October 27, according to the Las Vegas Review Journal.

His lawyer Larry Stein tells TMZ.com, "Shamefully, Ms. Osmond has fired Mr. Engemann 18 months into a 5-year written contract and seeks to enjoy the fruits of his labors without compensating him for his work."