A cartoon family of world-class underachievers is set to burst an enduring TV record.

The Fox network has ordered the 29th and 30th seasons of “The Simpsons,” carrying it through the 2018-19 season. This takes the animated series to 669 episodes, breaking the previous record for a scripted series set four decades ago with the Western “Gunsmoke,” which produced 635.

Family patriarch Homer Simpson was quoted as commenting: “Take that, ‘Gunsmoke’! You lost a race you didn’t even know you were running!”

The tale of mythical Springfield and the Simpson clan premiered in 1990 and recently aired its 600th episode.

It stars Dan Castellaneta as Homer and Julie Kavner as Marge, as well as Nancy Cartwright, Yeardley Smith, Hank Azaria and Harry Shearer. It airs Sunday at 8pm Eastern time (midnight UK time).