As The Simpsons celebrate their 25^th anniversary on Wednesday, the 85-year old who "performs" his voice for German audiences announced he had no intention of quitting any time soon.

"I'd have nothing to do, that's not for me", Norbert Gastell said. "We all get older, but if you do nothing you start to mentally decline. But if you keep working…that keeps you young."

Although the US cartoon series – which features Homer as the patriarch of a loving but dysfunctional family, including wife Marge, and kids Bart, Lisa and Marge – celebrates its quarter-century this week, that milestone is a little further off in Germany, where the series began transmission two years later.

Ganstell is assured of work for many years to come: the 17th series of the animation has only just been released on DVD in German, while his American colleagues have reached the 25th.

Of course, on screen Homer hasn't aged either. Estimating his age at 40 when the first episode was broadcast in the US on December 17, 1989, that would make the nuclear-power plant worker and donut addict 65 now – still some 20 years short of his German equivalent.

Gastell is, in fact, one of the oldest working dubbing actors in Germany, where most mainstream Hollywood films and TV shows are shown with voice-over, rather than subtitles – a lucrative line of work, which means many voice-over actors are stars in their own right.