"The Simpsons Guy", the big" Family Guy / The Simpsons" crossover event will be airing in September, here is everything known right now. 

It should be noted that "The Simpsons Guy" is technically an episode of "Family Guy," so much of it is from the Griffin's point of view as they enter the world of "The Simpsons."

Fox Aired a trailer and included in the footage was the following:

The Griffins walk up to the outskirts Springfield, with Lois asking, "Where are we?"

After they discover it's a town called Springfield, Stewie asks, "What state?", with Brian replying, "I can't imagine we're allowed to say."

As they walk into town and see the citizens and begin to notice they look, well, different from the Griffins, Peter warns the family, "Don't drink the water. Everyone here looks like they have hepatitis."

Bart skates around the street, showing off his skills. A much more uncertain Stewie than wobbles into frame on a skateboard as well, seemingly wanting to impress Bart, as he tells him, "Oh my god, that was great!" We also see Stewie try to convince Bart he doesn't wear diapers all the time.

Lastly, more of the big Peter vs. Homer fight scene was shown, beginning with them growling at each other...

Peter: "Simpson!"

Homer: "Griffin!"

The two begin comically punching each other, both of them exactly mimicking both the punch itself and their head swinging back for a while. They then begin pummeling each other and rolling around on the street, before Homer finally grabs Peter by his throat and begins to throttle him... at which point Peter freaks out and leaps back.

Peter: "What the hell? That really hurts!"

Homer: "I do it to my son all the time!"

Peter: "No wonder he's fat and stupid!"

Homer: "That's your son!"

Afew more details about the much-anticipated "Simpsons" "Family Guy" crossover episode were spilled today at Fox's comedy showrunners panel at Television Critics Association press tour.

In addition to featuring Homer, his family, and various Springfield residents, "Family Guy" Family Guy will include a cameo by Bob from "Bob's Burgers." According to "Family Guy executive producer Rich Appel. While the episode was written solely by the "Family Guy"team, the "Simpsons"producers and writers were invited to the table read of the script and offered a chance to give input. "We sent them the script, and I think between Jim [Brooks], Matt [Groening] and Al [Jean], they had one or two lines in the hourlong episode they asked to tweak," said Appel. "They gave us free rein."

"The Simpsons Guy" airs as the one-hour "Family Guy" season premiere on Sunday, September 28th on FOX.