Cher has prevailed in a long-running lawsuit that she filed against the widow of her former musical partner and husband, Sonny Bono.

Cher had received royalties from her chart-topping song catalogue with Bono since an agreement in their 1978 divorce settlement, that stated publishing revenue would be split evenly between the pair. Bono died in 1998, and his share passed to his heirs.

In 2016, widow Mary Bono – a politician who succeeded Sonny in the US House of Representatives following his death – exercised a feature of copyright law that allows songwriters and their heirs to win back rights they have signed away, arguing that she now owned Sonny’s publishing rights. Royalties were withheld from Cher in 2021, and the singer sued, with her lawyers arguing the termination clause used by Mary was “wholly inapplicable” to the royalty split agreed in the divorce settlement.

That case has now been found in Cher’s favour, with a judge ruling that “a right to receive royalties is distinct from a grant of copyright”, and that Cher should continue receiving financial compensation per the agreement.

Cher is owed around $418,000 of royalties that have been withheld during the dispute, thanks to the ongoing popularity of Sonny & Cher songs such as I Got You Babe and The Beat Goes On.

The US district judge who made the ruling, John Kronstadt, had already been leaning in Cher’s favour in a February hearing, saying then: “I don’t think the notice of termination can affect [Cher’s] notice of contractual rights.”

Neither Cher nor Mary Bono have commented on the judge’s decision. The Guardian has contacted representatives of each for comment.

Cher, 78, went on to a hugely successful solo career following her split from Bono, including a late-90s comeback generated by the global success of her single Believe.

She released her latest album, the seasonal collection Christmas, in October 2023. The single DJ Play a Christmas Song topped the Billboard adult contemporary chart, meaning that Cher has scored a No 1 hit on a Billboard chart for seven consecutive decades.