'Seinfeld' Reunion: Jerry Seinfeld Spills Details About 'Secret Project'

So what were Jerry Seinfeld and Jason Alexander doing outside Tom's Restaurant, anyway?

Seinfeld isn't saying exactly what the top-secret project is all about, but in an interview on WFAN-TV's Boomer & Carton show on Thursday, he did give away a few more details.

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Tom's Restaurant, of course, was used as the exterior of the fictional Monk's Cafe, frequented by Jerry, George (Alexander), Elaine (Julia Louis-Dreyfus) and Kramer (Michael Richards) in their 1989-98 hit series, Seinfeld. When an image of Seinfeld and Alexander together hit the Internet earlier this month, fans of the long-running show were abuzz with speculation about some sort of reunion. Reports also surfaced that it could be for a Super Bowl commercial of for an episode of Seinfeld's web series Comedians in Cars Getting Coffee.

Seinfeld said Thursday that it was neither -- adding, "But, it is not not those things, either. It's a secret project."

He added: "I gave you more now than I've given anyone. I told you what it isn't, and then I also told you that it isn't not that either."

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Seinfeld did say that it was filmed and that other Seinfeld characters were involved, confirming that Alexander is playing George. Asked if Alexander was surprised to get the call, Seinfeld quipped: "No, he remembers that he played that character for many years. He was not surprised that he was asked to play George."

Larry David, who co-created and executive produced Seinfeld, also was involved in the "short-ish form" project, though not on camera (nor was his voice; David voiced several roles in the series, most memorably that of late Yankees owner George Steinbrenner). Other locations also were used, but those didn't include Jerry's apartment.

Seinfeld added that while this is a "one-and-done" project, fans will get to see it "very, very soon."