You read it here first, and so did Larry David. While he couldn’t give away the entire plot in advance of the premiere this weekend, director Greg Mottola of the movie Clear History, which stars the co-creator of Seinfeld himself, confirmed that the Gazette defines a key plot point in the HBO film set on Martha’s Vineyard.

In one scene, a colonial facade in Los Angeles poses as the Gazette building and a character approaches the paper to deliver a tip, a story that’s sure to stop the presses. When Larry David’s character reads the headline, he’s shocked by the news. The film also stars Jon Hamm, Kate Hudson and Eva Mendes.

The Gazette is only one of a list of Island institutions featured in the film, which includes the Gay Head Light, the Chilmark Store and those narrow dirt roads leading to the north shore of the Island. Mr. Mottola has been vacationing here with his wife and kids for the past month, and he said the experience is somewhat surreal. As he sat noshing on a cinnamon roll on the porch of the Chilmark Store Thursday morning, he spoke of flashbacks to Clear History footage.

He half expects to see Mr. David careening past the porch in his gas-guzzling station wagon — which is exactly what happens in the film. The crew spent one day of filming exteriors on the Island, but financial constraints prevented total filming here. The film was originally a Fox Searchlight theatrical feature, but that management group was intent on filming in a far cheaper location — Wilmington, NC. Mr. Mottola and Mr. David agreed that the location wouldn’t do justice to the Island where Mr. David has been a longtime seasonal resident. “Wilmington looks nothing like the Vineyard,” Mr. Mottola said.

HBO agreed to film on location in towns north of Boston, operating out of an office in Beverly, where the scenery is similar and Boston accents are abundant. Crew members were drawn from the local population.

The film was conceived with the Island in mind, and efforts were made to incorporate accurate “Vineyard etiquette” into the fabric of the storytelling. Scenes include aerial views of the Gay Head Lighthouse and shots of electric cars driving along the coast of Oak Bluffs. There’s even a shoutout to Bartholomew Gosnold, who named the Island. But because they filmed late in the year, it was hard to capture the full roses in bloom in Edgartown or the dense greenery of up-Island.

“People who know the Island well will know we cheated, but a lot of people who saw the movie at the premiere thought we had shot the whole movie on Martha’s Vineyard,” Mr. Mottola said. Like Jaws, the movie gives the sense that the Island is smaller than it is in reality.

“I like movies where you have a sense of place, and it’s not generic,” he said.

Of course, it’s a Larry David version of Martha’s Vineyard. Since spending time here on the Island, Mr. Mottola has noticed that contrary to Mr. David’s unruly behavior in the movie, Islanders are remarkably gracious when they come to a standoff with another car on a one-lane dirt road. “I was surprised at how conflict-free the experience was,” he said. In truth, it seems the real Mr. David is much less disgruntled than his comedy might indicate.

“Larry’s comedy is often considered ornery and neurotic, but he is a shockingly happy person,” Mr. Mottola said. “He’s like somebody who is walking around whistling all day and I think he has tremendous affection for this place.”

The movie had no script, but instead relies on the improvisational sketch comedy of the actors, some of whom were not accustomed to taping a scene on the fly. “It was very creative, they were writing their own dialogue, they were creating their own characters completely,” he said. Mr. Mottola’s 2007 comedy Superbad also followed that style, but it still had a script. “It was like being in a writers’ room, hearing ideas, and deciding which ideas to build on, on the spot,” he said. Between takes, he and Mr. David would discuss what to riff on in the future.

“Larry said to me at the beginning, this is going to be hardest thing you’ve ever done, and he was right,” he said. He said the improv benefitted from the familiarity Mr. David has with the Island. Mr. Mottola admires Mr. David’s comic genius and said he sometimes deferred to him for directing decisions. “He’s right about people so often, he sees things that other people don’t see,” he said. “I wanted it to be Larry’s voice.”

The first 15 minutes of the film show the ruination of Mr. Flomm’s marketing career in San Jose, Calif., in which an argument with his boss (Jon Hamm) over the name for a new electric car model leads him to pull his shares from the company. When his boss becomes an overnight success, Mr. Flomm becomes a laughingstock — known to all as the guy who missed out.

In an effort to literally clear his history, Mr. Flomm moves to the Vineyard and adopts new name: Rolly DaVore. He settles in among the locals, shaves his overgrown head and facial hair and tries to duck the public eye, working as an aide to an elderly woman. But when his former boss builds an ostentatious McMansion on the Island, Mr. Flomm/DaVore seeks revenge. “He totally butts into his world, and makes him crazy,” he said.

It’s a film about the struggle of the little guy "who makes the mistake of comparing himself to the super successful guy, and not appreciating what he has,” Mr. Mottola explained. “It’s meant to be that his life on the Vineyard is actually not bad at all.”

The film will be shown exclusively on HBO and will not play in theatres. It airs August 10 at 9 p.m.