Singer and actress Cher has sued the widow of her former musical partner and ex-husband Sonny Bono over royalties for Sonny and Cher songs, including I Got You Babe and The Beat Goes On.

In a federal lawsuit filed in Los Angeles on Wednesday, Cher alleges that former US congresswoman Mary Bono and other defendants have attempted to terminate provisions of business agreements Cher and Sonny Bono reached when they divorced in 1975 that entitled each to 50% of songwriting and recording royalties.

The lawsuit claims that Sonny Bono’s heirs filed notice in 2016 that they were terminating some of his song licensing agreements, but they “did not terminate, and could not have terminated” his agreements with Cher.

The breach of contract lawsuit alleges that the damages to Cher total at least one million dollars (£730,000).

Mary Bono’s lawyer Daniel Schacht said the family’s moves are within their rights and the law.

“The Copyright Act allows Sonny’s widow and children to reclaim Sonny’s copyrights from publishers, which is what they did,” Mr Schacht said in a statement.

“Representative Bono remains open to continuing a private discussion about this, but we are confident that, if necessary, the court will affirm their position.”

Cher, the 75-year-old Grammy, Oscar and Emmy-winning singer and actress known for solo hits including Believe and film roles including Moonstruck, began performing as a duo with Sonny Bono in 1964.

The two later had a TV variety show, and enjoyed a huge hit single with I Got You Babe in 1965, which reached number one in the UK, US and Canada. They were married from 1969 to 1975.

Sonny Bono became mayor of Palm Springs in California and was later a congressman for the area. He died in a skiing accident in Lake Tahoe in 1998. Mary Bono, his fourth wife, later won his seat.