The producers of the hit animated comedy Family Guy have given fans their first glimpse of the upcoming crossover episode that will bring Family Guy's Griffin family to Springfield, the home of The Simpsons.
But as they began to take questions from fans at this year's Comic-Con fan convention in San Diego, they had to take not one but three queries from an unlikely, and unexpected, source.
The Simpsons creator Matt Groening, who had gate-crashed the Family Guy panel and quietly taken his seat, took the microphone to ask his one-time rivals three questions about their plans for the highly-anticipated "crossover" episode.
The first was, do you have any advice for a young, struggling animator? The second, what is Matt Groening really like? And the third, can you "kiss my ass" a little bit more please?
While Groening's appearance was clearly an orchestrated stunt of the kind Comic-Con attendees have become accustomed to, it was also seen as the legendary creator of The Simpsons giving his blessing to the planned crossover episode.
The episode will screen later this year as a one-hour season opener for the upcoming 13th season of the show. Though they are creatively distinct and, for a time, were even rivals of a sort, both shows are owned by 20th Century Fox's television studio, Twentieth Television.
The presentation featured Family Guy producers and cast, including Steve Callaghan, Rich Appel, John Viener, Seth Green, Peter Shin and Mike Henry.
In the clip screened at Comic-Con, Peter Griffin and Homer Simpson bond over donuts but later disagree over the taste difference between their preferred beers, Pawtucket Patriot Ale (from Family Guy) and Duff Beer (from The Simpsons), while Bart Simpson and Stewie Griffin bond making prank phone calls and skateboarding.
The clip also featured other characters such as Ralph Wiggum and the aliens Kodos and Kang, an extended fight sequence between Peter Griffin and Homer Simpson and an incident at Springfield Nuclear Power Plant.
20th Century Fox announced the episode earlier this year, and The Simpsons' producer Al Jean discussed it briefly at the annual US television press tour earlier this month, noting that it was in fact a Family Guy episode and - technically - not in his purview.
According to US media, The Simpsons cast members Dan Castellaneta, Julie Kavner, Nancy Cartwright, Yeardley Smith and Hank Azaria all worked on the episode.
The two programs have an historic rivalry - though it was, to some extent, fuelled by South Park creators Matt Stone and Trey Parker, whose disdain for Family Guy is well known - but that rivalry has, in recent years, softened.
Simpsons star Dan Castellaneta did an audio cameo in a 2012 episode of Family Guy, and Family Guy's creator Seth MacFarlane guest starred in an episode of The Simpsons in 2013.
Although both programs are owned by Twentieth Television, The Simpsons is owned in Australia by the Ten Network and Family Guy by Channel Seven, which means Seven will own the broadcast rights to the crossover episode.
Seven has not announced its plans for the episode, or an airdate.