WATCH: That Top-secret 'Seinfeld' Reunion You've Been Waiting For

The secret Super Bowl project reunited Jerry Seinfeld and other characters from the '90s show - in a Super Bowl ad for the comic's Web series.

The top-secret "Seinfeld" reunion that fans had been speculating about finally saw light on Sunday, during Super Bowl XLVIII.

Jerry Seinfeld joined forces with Jason Alexander (aka George Costanza) and Wayne Knight (aka Newman) at Tom's Restaurant, the site of many a "Seinfeld" scene, to reprise their roles from the '90s sitcom.

The reunion was actually an ad for Seinfeld's latest series, "Comedians in Cars Getting Coffee," in which the comic drives around in a classic car with fellow funny people, as they drink coffee and share stories along the way. The full episode of him with Alexander can be viewed on the Crackle website.

Following rampant speculation about a photo making the rounds online of Seinfeld and Alexander walking into Tom's Restaurant, he told a sports radio show last week that a "short-ish form" project was in the works and that it would go public "very very soon."

Seinfeld also described the project as a one-off, or in his words "one and done."

"Comedians in Cars Getting Coffee," the Web series from Crackle, has featured Louis C.K., Tina Fey, Sarah Silverman and Howard Stern, among others.

It's gotten more than 25 million streams, making it Crackle's No. 1 original series, according to the Hollywood Reporter.

John Minchillo/Invision/AP
Screen grab via Crackle.com