The actors who provide the voices for The Simpsons have stopped work in a pay dispute involving the renewal of their three-year contracts, it is reported.
The Simpsons is moving into its 16th series on US TV
Hollywood trade paper Variety said the six actors had not shown up for two script readings in the past few weeks.
Variety said the row involved actors including Dan Castellaneta, who voices Homer, Julie Kavner, who plays Marge, and Bart actress Nancy Cartwright.
It said actors' representatives were negotiating new deals "to no avail".
Others reportedly involved are Hank Azaria - the voice of Moe - Harry Shearer, who plays Mr Burns, and Yeardley Smith, who voices Lisa.
Variety said the actors' failure to show up had held up production on the hit animation's 16th series.
A previous dispute among staff on the show took place in 1998, when the actors were making $30,000 (£16,000) per episode.
Producers Twentieth Century Fox TV had hired casting directors to replace staff before a new deal was worked out and production resumed.