Cher also challenges accounting on a second compilation, 2002's "The Very Best of Cher." UMG allegedly allowed the album to be distributed by a division of Warner Music Group but accounted to Cher on a royalty basis as though UMG had sold the records itself, thus decreasing her share.

"UMG Recordings is underreporting and underpaying the royalties due to plaintiffs based on UMG Recordings' improperly accounting to plaintiffs based on a royalty rate instead of their respective shares of net receipts."

Cher also claims that UMG improperly deducted $328,662 in television advertising expenses and a 6.5 percent service charge in reporting revenue from the 1999 greatest hits collection, and that more money is owed from 2004 through 2008. But she has not yet audited the label's books for those years.

Cher and Bono came to prominence in 1965 when their single "I Got You, Babe" hit No. 1 on the Billboard chart, and she has since become the only female recording artist to have a Top 10 hit in each of the past five decades.

When Cher and Bono divorced in 1977, they agreed to split revenue from the songs recorded together. After Bono died in a ski accident in 1998, one-third of his interest passed to wife Mary Bono Mack, and one-sixth interests were split amongst his kids. Bono Mack, as well as Cher's daughter with Bono, Chastity Bono, are plaintiffs in the case, as are Bono children Christy Bono, Chianna Bono and son Chesare Bono.

"Universal is playing a game of catch-me-if-you-can with one of the most popular and iconic artists of all time," said Cher's lawyer, Mark Passin, of Robbins Kaplan. "Unfortunately, record companies have learned over the years that they can increase their bottom line by underreporting royalties to artists."

Music producer Snuff Garrett is also a plaintiff. He claims he is entitled to a 50 percent pro rata share of royalties from some of the recordings based on a producer's deal with MCA Records.