George Santos is saying a big "f*** you" to everyone at HBO ... vowing to go after the channel/streaming platform for developing a new movie about his controversial political career.

The recently-booted congressman sounded off to TMZ after HBO optioned the rights to Mark Chiusano's new book "The Fabulist: The Lying, Hustling, Grifting, Stealing, and Very American Legend of George Santos" ... blasting it as defamatory and misappropriating his name and likeness.

Santos says he has zero involvement in the "fictitious story" the movie plans to sell to the American people ... and is vexed about the filmmakers and book's author not speaking to him or getting authorization to write about him.

However, he says he's not concerned about how he'll be represented in the doc ... because he's working on a project that best fits his narrative. As for HBO, Santos vented, "F*** them and their chicken s*** deal with no inside information or reality of facts."

We're not sure how he'll navigate any potential comeback trail following his expulsion from Congress last week ... but ya gotta applaud the hustle.

The decision came following a controversial time in office, which included multiple felony charges.

For now, he's been busy advising his fans to "let the haters hate" on Cameo for $200 a vid.

BTW, we talked to the guy whose book this HBO film is based on ... and he tells us he tried his best to get GS to get involved in the story, to no avail though.

Author Mark Chiusano -- who published 'The Fabulist' this year -- joined us on "TMZ Live" Tuesday to discuss Santos' threats of action against the movie ... and he says he's heard it all before. The guy also stands by his work, and thinks he did a good job of representing things as they are.