In the two seasons before this one, Larry David’s “Curb Your Enthusiasm” pushed politically correct notions of Jewish identity and race to cringe-worthy and hilarious extremes.

David, playing an exaggerated version of his misanthropic self, briefly made nice when he mistakenly believed he had been adopted and was not born Jewish, then he returned to his callous self when his wife — now estranged — took in a black family that had been displaced by Hurricane Katrina.

“So your last name is Black,” he said to the family upon their first meeting, arriving late to pick them up at the airport. “That’d be like if my last name were Jew: Larry Jew.”

Larry David (right) gathers with the “Seinfeld” cast on the set of Jerry Seinfeld’s apartment.

Now three episodes into its seventh season, HBO’s “Curb” is currently tackling a different kind of faux pas that the real David has condemned: the sitcom reunion show.

This reunion is of “Seinfeld,” which David co-created with comedian Jerry Seinfeld. It ended 11 years ago after a highly successful nine-year run on NBC.

Although David, 62, had often dismissed the notion of a “Seinfeld” reunion as “lame,” he said at a press event earlier this year that it dawned on him that a fictional “Seinfeld” reunion on “Curb” could be funny.

The four stars of “Seinfeld” agreed — and the reunion plotline began with the Oct. 4 episode.

Season seven opened with Larry’s wife, Cheryl, having left him, forcing him by social convention to care for his girlfriend — the matriarch of the Black family clan (Vivica A. Fox) — who may have cancer.

The show has been playing out like an amped-up rant about life’s small irritations and unwritten “rules,” as was the form made famous by “Seinfeld,” but now with “Curb’s” nasty edge. Among the topics: the etiquette of whether one should help oneself to food from a friend’s refrigerator (“liquid’s OK,” as one character tells an irate Larry), and having to be nice to not-so-nice people who have cancer.

Based on the season’s first three episodes, it remains unclear whether “Curb” will carve new territory in its lampooning of the Hollywood rich, or if Larry’s habit of getting himself in trouble through a series of faux pas will ratchet up with ever-escalating humiliations for the character.

But seeing David on the screen with his “Seinfeld” colleagues in this week’s episode was more than satisfying, and sidesplitting.

The four main “Seinfeld” characters will appear in five episodes as themselves, separately negotiating a “Seinfeld” reunion show with Larry. Then, after not having appeared onscreen together since 1998, Seinfeld, Julia Louis-Dreyfus, Jason Alexander and Michael Richards will reunite for the “Curb” season finale.

Larry David and Seinfeld discuss a potential cast reunion in a scene from “Curb Your Enthusiasm.” photos/hbo/doug hyun

To set his reunion plan in motion — a plan that includes ulterior motives (surprise!) that are less than honorable (Larry wants to win back Cheryl by casting her as the ex-wife of George Costanza) — Larry disingenuously meets with each actor to hawk his proposal.

“Why would we do something like this?” a skeptical Jerry asks, reminding Larry that usually “you would look [at reunion shows] and you’d make that face, that very judgmental face of yours … you’d criticize and downgrade them for it, that’s your style.”

Jason Alexander doesn’t buy Larry’s idea that George, his “Seinfeld” character, could have been married for a time, because he says George is “unlovable — a jerky, shmucky little character.”

But Alexander does like the idea that a reunion show might make up for “Seinfeld’s” finale, lampooned in real life by critics for its harsh condemnation of the characters, who wind up in jail for their selfish behavior. This irks Larry, who — like the real-life David — contends there is “nothing to make up for.”

Here’s hoping that this season answers one other lingering question about the older sitcom: Why was the obviously Jewish Seinfeld never openly described as Jewish on the show?

“Curb Your Enthusiasm” airs Sundays at 9 p.m. on HBO.