Seth Rogen Writes a "Simpsons" Episode

Seth Rogen has fulfilled a life-long dream and it's not playing a superhero or kissing Katherine Heigl. The comedic actor has co-written and lent his voice to an episode of "The Simpsons."

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

In the episode, entitled "Homer the Whopper," Rogen plays a trainer who must get Homer Simpson into shape to play Everyman, a superhero created by Comic Book Guy.

"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.

The story is also based on Rogen's personal experience getting into shape to play the Green Hornet. He is the second "Simpsons" guest to star and write an episode.

"Homer the Whopper" will be airing on Sunday Sep 27 and will kick off the 21st season of the hit animated series.