Fans of “Seinfeld” and “Curb Your Enthusiasm” know that this Sunday, worlds will collide. That’s when Larry David’s brilliant HBO show “Curb” reunites Larry with the cast of “Seinfeld.” In Sunday’s episode, self serving Larry decides to produce a “Seinfeld” reunion show for NBC as a way of getting back his estranged wife, Cheryl (Cheryl Hines).’ Logical? Don’t ask. Somehow he persuades Jerry Seinfeld, Jason Alexander, Julia Louis-Drefyus and Michael Richards to go along with him.

The story arc begins on Sunday but then lays dormant for two episodes. On October 25th, in episode six, it picks up again through episode 10. Last night HBO screened 3 and 6 for an invited audience at the Time Warner Center that included Larry David, Jerry and Jessica Seinfeld, comic Susie Essman (who plays Larry’s agent’s wife), Patricia Clarkson, Regis and Joy Philbin, Caroline Kennedy and Ed Schlossberg, Bob and Lynne Balaban, Steve Buscemi, a variety of media types including Dan Abrams, Ashley Banfield, Hoda Kotb, Dave Zinczenko, Kenneth and Maria Cuomo Cole, Kerry Washington with writer Lawrence O’Donnell, Joni Evans, and so on. It was quite a group.

More to the point: in episode 6 fans will see something never seen before ‘ David and Seinfeld together, in a scene of improvised dialogue, riffing off each other. It’s brilliant, recalling Mel Brooks and Carl Reiner. In Jerry’s comic book world, it’s like watching a match up of Batman and Superman. Seinfeld told me that was exactly right. “We approached it like a meeting of super heroes.”

What becomes clear this Sunday and even more obvious later: “Seinfeld” and “Curb” are unlike each other. What’s sort of amazing is watching how the Seinfeld Four become enmeshed in fictional Larry David’s world, or rather victimized by it. The Larry David “character” of “Curb” lies, manipulates, and maneuvers through life. We’ve never really seen him work. Now we see him trying to produce the “Seinfeld” reunion and in the process, have to deal with these actors who once starred on his hit show. (It’s very meta-meta, too, since it’s actors playing parts of actors who once played parts. Yikes!)

Already in the first two episodes this season, “Curb” has moved into a hyper gear. It’s super charged with ideas, weaving semantics throughout, exploring situational absurdities. They are literally piling on. Last week, Larry man-hugged an acquaintance reluctantly and broke the guy’s reading glasses ‘ dangling on a cord ‘ by accident. The man wants to send him a bill for repairs. A debate ensues about the hug that turns into one of many existential plays within a play.

Now David and Seinfeld add the four actors from the original show, and it’s like a quadruple ping pong match. In episode 6, Jerry and Larry (who is part Jerry and part George) are working in an office at a desk, trying to write. An absurd plot begins with their secretary, leading the men to describe each other’s strong suits and weaknesses. It’s marvelous, not to be missed. Forget “30 Rock.” This is what the Emmy was invented for. Don’t miss’ a word of it.

And P.S.: Meg Ryan ‘‘star of comedies from the late 80s and early 90s ‘ has an uncredited cameo.