Watch What Happens When 'Family Guy' Meets 'The Simpsons'

You no longer have to imagine what would happen if Peter Griffin met Homer Simpson, because a first look at the " Family Guy"/"The Simpsons" crossover episode has been released.

The extended five-minute clip of the Griffins' much-anticipated visit to Springfield for the Sept. 28 one-hour show was screened during the "Family Guy" panel at Comic-Con in San Diego on Saturday.

It opens with the Griffins somehow winding up in Springfield, where Peter and Homer initially bond over beer and donuts while their sons Stewie and Bart make prank phone calls and skateboard together.

(E3 '14/YouTube)

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Naturally, Peter and Homer's nascent friendship takes a dark turn when Homer says Peter's Pawtucket Patriot Ale tastes a lot like Springfield's Duff Beer.

When Peter says the ale "may have been inspired by Duff, but … takes it in another direction," it's also a dig at the shows' similarities. "Family Guy" arrived years after "The Simpsons" became a hit.

The two men duke it out in an epic fight that also involves a runaway bus and a nuclear meltdown.

Watch what happens when these animated worlds collide below: