LOS ANGELES— ''TO Jerry's credit, he never censored anything,'' said Larry David, the co-creator and executive producer of ''Seinfeld'' for seven years. ''But he vetoed this.''
''This'' is an incest-themed story line that never showed up on ''Seinfeld'' but that Mr. David was taping two weeks ago for his new show, ''Curb Your Enthusiasm,'' starting on HBO in October. Mr. David, who plays himself, is asked by an old girlfriend to go with her to a support group for incest survivors. He tries to worm out of it, arguing that abuse by a stepfather might not count. ''With all due respect to your ordeal,'' he says. ''There might be a whole other group for stepthings.''
He goes to the meeting and makes up an incest event of his own. Later, he will pay, both for agreeing to accompany his ex and for lying. In Mr. David's world, no bad or good deed goes unpunished.
Mr. Seinfeld isn't sure he vetoed incest. ''I don't really remember that,'' he said. But you can see why such a plot twist -- or twisted plot -- might have raised red flags at their old network, NBC. On HBO, such sensitivities fall under the forgiving umbrella of creative license. And the man who wrote and supervised the other writers of one of the most acclaimed and lucrative sitcoms of all time gets a lot of license.
Larry David is hardly a household name. But few households do not know the intimate details of his life, his obsessions, his euphemistic catchphrases (''master of my domain''). He, not Mr. Seinfeld, had the wacky neighbor named Kramer. He once ruined a suede jacket worn for a scary meeting with a girlfriend's father. He was the model for Jason Alexander's portrayal of Jerry's alter ego, George Costanza. And yet, the only on-air exposure his millions of viewers ever got to Mr. David was his uncanny vocal impersonation of George Steinbrenner.
HBO subscribers got a glimpse of him, though, in an hourlong mock documentary, also called ''Curb Your Enthusiasm,'' which the channel has shown every so often since last October. In it, a camera crew purports to follow Mr. David, who is 52, around as he works the comedy club circuit in preparation for a supposed HBO stand-up special. It ends with Larry chickening out of the special. Other characters include his wife and his manager, who happen to hate each other, various alleged HBO executives and cameos by minor celebrities. ''Curb Your Enthusiasm'' was directed by Robert Weide, a documentary filmmaker whose specialty is comedians (most recently Lenny Bruce). The whole thing was a put-on, but seemed so real that a friend of the actress playing Mr. David's wife was offended that she wasn't invited to their wedding.
Imagine ''The Larry Sanders Show'' -- only more so. Coincidentally in sync with ''Survivor'' and the current mania for voyeuristic programming, Mr. David has created a hybrid of extreme reality and extreme comedy. All dialogue is improvised from a loose five-page outline that he has written for each of the 10 episodes of the series. The stand-up scenes and mock-documentary gimmick have been dropped. But it still has the same verite feel. It's deadpan in a way that will certainly appeal to critics if not a mass audience expecting the second coming of ''Seinfeld.'' In some ways ''Curb'' is subtler and more nuanced, but with the same unmistakably Seinfeldian structure of snowballing bad luck. Mr. David's desert island may be Los Angeles, but that doesn't make survival any easier.
''This show is about a guy trying to get through the day with a little dignity attached,'' said Chris Albrecht, HBO's president of original programming. Mr. Albrecht has known Mr. David since the 1970's, when they were both unsuccessful comics at Catch a Rising Star here. ''Larry's an incredible everyman,'' he said. An everyman reported by Forbes magazine to have hit a $242 million jackpot when ''Seinfeld'' was sold into syndication. But unlike Mr. Seinfeld, who collects Porches like baseball cards, Mr. David has never really been able to enjoy his windfall.
''Mostly what it does is make you apologize a lot,'' he said. Unlike the dwarfish, irritable Costanza, Mr. David is a rangy character with a quick smile. He has a penchant for wide-wale cords and untucked shirts. To look at him, you wouldn't know he was loaded, but out here, you never can tell. By the pool of the once-glamorous Roosevelt Hotel on Hollywood Boulevard, he ate his lunch during a break in the incest group scene and subjected himself to questions about the real Larry David. ''I have quite a house,'' he said. ''People come over and I go, 'I know, I'm sorry.' ''
Mr. Albrecht said Mr. David's worldview could be summarized as, ''I know, I should have had the chicken.'' Regret, remorse -- those are old friends of his comedy. Long ago, he taught himself never to think about the future because it was too painful for him to contemplate. ''To regret the past -- yes!'' he said, his voice rising to a characteristically Costanzan shout. ''To regret everything about the past -- certainly!''
The present is no picnic either, what with its habit of turning into the regrettable past. In one episode of ''Curb Your Enthusiasm,'' in a car-phone conversation with his manager, he refers to his wife as ''Hitler.'' (Verbalizing things that the rest of us might think but would never say is a David specialty.) The manager is in his own car, on his speakerphone, but fails to mention that his parents are in the back seat. So offended are they by the Hitler remark that Mr. David is later called upon to offer an apology. (Another speciality is awkward moments.)
''People are constantly screaming at me on the show,'' he said, allowing that this is a slight exaggeration of his relatively civilized existence as a supersuccessful Los Angelino. ''When I was living in New York, there was a lot of screaming in my life. I would just get into these altercations all the time. Being in public, dealing with shopkeepers, just trying to cross the street -- things like that. I'm not in a position where I can scream like that anymore. I'm not quite as anonymous as I was. And I guess things aren't as vital to me as they were then.''
It was during those struggling stand-up days in New York when Mr. David and Mr. Seinfeld became friends. They'd meet at coffee shops and talk for hours about things like laundry.
As Mr. Seinfeld recalled, ''What we had in common was both of us had the ability to focus deeply on something small, to blow small things out of proportion.'' One of them was on his way to becoming one of the most successful comedians in the country. The other remained a comic's comic, meaning he'd perform in front of five people and they'd boo him off the stage. Interviewed in the ''Curb'' special, Mr. Seinfeld said Mr. David would address the audience as ''You people,'' which, as Mr. Seinfeld would tell him, ''was a little distancing.''
The highlight of Mr. David's pre-''Seinfeld'' career was a stint writing and performing on ''Fridays,'' ABC's short-lived ''Saturday Night Live'' clone. Also in the ''Fridays'' cast was Michael Richards, later to play the fictional version of Mr. David's old neighbor Kramer.
The conventional wisdom on why the Seinfeld-David collaboration worked so well is that Jerry made Larry palatable to a mass audience. They both hate the inevitable Lennon-McCartney analogy. ''Whether it was a dark thing or a light thing,'' Mr. Seinfeld said, ''we almost always agreed on what was funny and what wasn't funny.''
The major point of contention was that, almost as soon as they started doing the show together, Mr. David wanted to stop. He had no more ideas. He constantly worried about keeping it funny. It was too stressful, he'd complain. After the show had been on for a few years, executives from Castle Rock, the production company, told its creators that they were in a position to make some serious money on the show. Mr. Weide recalled Mr. David's reaction to this news: ''Larry said, 'Great! Now we can take it off the air.' '' He finally left in 1996, returning only to write the series finale in 1998.
Mr. David's first outing without Mr. Seinfeld was not auspicious. ''Sour Grapes,'' the 1998 movie he wrote and directed, was a black-humored morality tale of two cousins who fall out over money: one lends the other the quarters he uses to win a slot machine jackpot in Atlantic City. Roger Ebert called it ''a comedy about things that aren't funny'' and didn't stop there. ''I can't easily remember a film I've enjoyed less,'' he said. Janet Maslin, writing in The New York Times, was kinder: '' 'Sour Grapes' should soften the blow of 'Seinfeld's' imminent extinction with the good news that, in Mr. David's merry world of hair splitting and back stabbing, the dream definitely lives on.''
Moviegoers did not agree. Expectations could not have been higher, except maybe for the final episode of ''Seinfeld,'' which also received less-than-glowing reviews. ''Let them try to write it!'' Mr. David said on the set last week. ''I shouldn't have kept the script a secret.'' Wincing with remorse, he still feels burned by the overhype that surrounded that show.
No danger of that happening this time around. Mr. David is determined to undersell himself, even in the title. HBO wanted to give him a billboard on Sunset Boulevard. No way. ''I don't want to do anything,'' he said. ''I can't stand reading anything that I've said. I hate that kind of attention. I don't want articles and pictures.'' His action plan: ''Let the show sneak up on people.''
In his vampiric fear of the limelight, Mr. David is more like a writer than a performer. But he is remarkably relaxed in front of the camera, quite at ease playing himself. Much of the comedy of the series is simply his poker-faced reactions to the terrible situations he has wrought. And the improvisational style of the show, having to be funny on his feet, leaves him less time to worry about his acting, or how he looks.
Over lunch, he wondered if he was the first bald star of a sitcom since Phil Silvers, whose show he loved, growing up in the Sheepshead Bay section of Brooklyn. ''I was thinking about it, but I couldn't come up with any. I guess, Don Rickles.''
Jeff Garlin, who plays Larry's manager, said Mr. David's point of view is defined by three things: ''anxiety, anger and despair.'' Despite which he manages to be an extremely friendly, likable and funny guy to be around. Here at the Roosevelt Hotel, attended to by a personal assistant who looks like Liv Tyler, possibly better, and no network suits in sight, he seemed . . . happy.
''He's having as good a time as I've ever known Larry to have,'' Mr. Weide said.
This miserable fictional Larry is not quite him, after all. His wife and manager don't actually hate each other. Really, they don't.
Photos: Larry David, second from left, on the set of ''Curb Your Enthusiasm,'' participates in group therapy in an episode that examines incest. (Photographs by Marissa Roth for The New York Times)