Seth Rogen has fulfilled a dream by becoming only the second visiting celebrity to write and act in THE SIMPSONS since Ricky Gervais appeared in 2006, Variety reports.

"As a writer, it always just seemed like the Holy Grail," Rogen said. "I can die a happy man now."

The episode, which was penned by Rogen and writing partner Evan Goldberg with the show's writers, riffs on the actor's pre-filming fitness regimen for GREEN HORNET, which is set for release next year.

Rogen plays a trainer in HOMER THE WHOPPER and is tasked with getting Homer Simpson in superhero shape.

"We wanted to comment on how Hollywood generally ruins these movies. The whole joke is Homer is cast to play a guy who's an everyman and they try to make him into this physically fit guy," Rogen said.