Cher is asking a federal judge to force Sonny Bono's widow to cover her $1 million (£750,000) legal tab.
The move comes after the singer prevailed in her royalties war with Mary Bono.
Cher and her lawyers say Mary should pay the bill because she tried to "misuse" the termination provisions of the Copyright Act to illegally "obtain a windfall" at Cher's expense.
They claim Mary then "dragged this case out for five years by taking patently unreasonable positions".
In the divorce settlement, Sonny had assigned Cher a 50 per cent share of his composition royalties for hit songs including I Got You Babe and The Beat Goes On. Cher also got a 50 per cent share of the musical recordings they made together.
Cher's grant was untouchable, the judge found.
"Defendant argued, repeatedly and frivolously, that a federal statute that expressly states it does not affect state-law rights somehow extinguishes those state law rights," the new motion for legal fees states. "Cher prevailed completely."
Cher's new motion for fees says she was forced to run up a bill of $1,023,605.50 (£762,641.17) with her lawyers to successfully defeat Mary's "improper attempt at termination".
Cher rose to fame alongside Sonny in the 1960s before building a decades-long solo career that has brought her Grammy, Oscar and Emmy wins.
Sonny died in a skiing accident in 1998, leaving Mary in charge of his estate. His music publishing grants became eligible for termination beginning in 2018.
A hearing on Cher's request for the fees is set for 23 February.
