James Gandolfini plays mafia head Tony Soprano

Gandolfini, who plays mob boss Tony Soprano, is unhappy that he was not told the show's creator David Chase was being paid $20m (�12.4m) for the coming season.

The legal case filed in the Californian Supreme Court says this is in violation of Gandolfini's contract and he should now be free of it.

It also says the contract exceeds the legal seven-year limit for personal services.

HBO says it is surprised by the legal action but sees the move as an actor attempting to renegotiate a binding contract.

Gandolfini's lawyer, Martin Singer, says the actor has not ruled out carrying on his role as the head of the mafia family.

"Our legal position is that there is no obligation for James Gandolfini to perform services for the coming season," said Mr Singer.

"There have been negotiations going on for our client to potentially return.

"They haven't reached an agreement and we have until 24 March to evaluate what to do. That is the day they've requested for him to come back to work."

Considerably less

Gandolfini earns $400,000 (�250,000) per episode which is in line with Martin Sheen's pay packet for The West Wing and Frasier actress Jane Leeves.

But it is considerably less than the $800,000 (�500,000) cheque picked up by Ray Romano for Everybody Loves Raymond and the $1.6m (�1m) paid to Kelsey Grammer for Frasier.

Gandolfini renegotiated his contract in 2000 in a $10m (�6.2m) deal for two seasons, following the success of the show.

Each series of the Sopranos runs for 13 episodes, compared to 22 for Friends and Frasier, but filming takes up the same amount of time.

Chase has said he will bow out after the fifth series, but HBO are still trying to change his mind.