Cher is suing the widow of late her musical partner and former husband Sonny Bono, accusing her of wrongly seeking to revoke the singer’s ownership rights to “I Got You Babe” and other iconic hits created by the duo.

In a complaint filed Wednesday (Oct. 13) in California federal court, Cher asked a judge to stop Mary Bono from invoking copyright law’s so-called termination right – a provision that allows creators to claw back control of rights they signed away decades prior.

Cher said the provision simply does not apply to her 1978 divorce agreement with Sonny, which gave her a permanent fifty percent cut of royalties from their songs.

“This action has become necessary because now, more than forty years after plaintiff received her fifty percent ownership of her and Sonny’s community property, Sonny’s fourth wife and widow … claims that a wholly inapplicable statutory termination provision … has undone plaintiff’s ownership of her royalties from the songs and recordings that she and Sonny made famous during their marriage,” Cher’s attorneys wrote in the lawsuit.

Cher is repped by Peter Anderson at Davis Wright Tremaine LLP, who has defended The Weeknd in high-profile copyright lawsuits and won the big “Stairway To Heaven” case on behalf of the members of Led Zeppelin.

When reached for comment on the accusations, Bono – a former congresswoman, who married Sonny in 1986 – directed Billboard to her attorney, who did not immediately return a request for comment.

The case is the latest major music industry clash over the termination provision. Two pending class actions filed by musical artists are seeking to use it to regain control of masters owned by Universal Music Group and Sony Music Entertainment. Earlier this week, a co-founder of KC & the Sunshine Band filed a similar termination case to win back compositions controlled by Sony’s EMI Longitude Music.

Sonny and Cher started performing together in 1964 and married in 1967, rising to fame with major hits like “I Got You Babe” and “Bang Bang.” But the pair split up in 1975, finalizing their divorce with a settlement agreement in 1978. Bono died in 1998 as the result of skiing accident.

Under the terms of that divorce deal, Cher says she was assigned a fifty percent share of “their rights in musical composition royalties, record royalties, and other assets,” throughout the world and in perpetuity.

According to Wednesday’s lawsuit, that agreement went unchallenged until last month, when Mary Bono’s representatives notified Cher that they had invoked the termination right and would soon stop paying out royalties.

In her complaint, Cher made various arguments for why Bono cannot use the termination right; she also argued that any such termination would not apply to global rights, or agreements made after 1978. She also accused Bono of breaching contracts by refusing to pay royalties.