The two American families will meet one another in the Simpsons' hometown of Springfield, although the episode will air on "Family Guy." Homer, Marge, Bart, Lisa and Maggie will get to know Peter, Lois, Megan, Chris and Stewie, and while the two ladies will strike up a friendship, their husbands will launch into a heated argument over which is the superior beer: Duff or Pawtucket.

The Griffins came to Fox in 1999, ten years after the Simpsons. There are a lot of similarities between Seth MacFarlane's show and that of Matt Groening. Caricatures of the average American family, both shows portray quirky and simple-minded dads, with reasonable housewives providing the "straight man" element. Both families also have three kids and a pet.

On September 29, "The Simpsons" will enter its 25th season, setting a new US record for a prime-time series. The same date will mark the premiere of the 12th season of "Family Guy."