The former manager of The Killers is suing the US rock band for $16m (£9.1m) for an alleged breach of contract.
Brandon Flowers and The Killers performed at Live 8 in Hyde Park
Braden Merrick has begun legal action at a Las Vegas court, saying he was unfairly fired last May, two years before his contract was due to end.
Mr Merrick's lawyer said his client believed he was "entitled to a percentage" of the band's income.
The band's lawyer Robert Reynolds said they would defend the "absolutely meritless" claim.
Howard King, Mr Merrick's lawyer, said: "As soon as he made them superstars they decided to stop paying him.
"He's entitled to a percentage of their income for his services as a manager and a producer."
The two sides had been negotiating a settlement before Mr Merrick launched his legal action.
Mr Reynolds said the band were surprised by the claim.
"The only statement the band would like to make at this time is that the claims alleged by Mr Merrick are absolutely meritless and we intend to defend this action vigorously," he said.
The Killers formed in Las Vegas in 2002 and have released hit singles including Mr Brightside and All These Things That I've Done.
Their first album Hot Fuss sold more than six million copies, according to Mr Merrick's claim.
The Grammy-nominated act recently began recording a second album.