It’s a few weeks past April Fools’, but close enough to make the grand scam of “The Hoax” all the more apropos.

Based on a stranger-than-fiction yarn that strains credulity but really, truly, honestly occurred, “The Hoax” is about Clifford Irving, the desperate, broke and middling author who, in 1971, approached a New York publisher with a project: the authorized biography of billionaire recluse Howard Hughes.

After presenting documents purportedly written by the eccentric industrialist – documents verified by independent analysis – Irving came away from McGraw-Hill with a check for almost $1 million. Then he went to work on the book, supposedly in collaboration with his subject.

And he made the whole thing up.

As the brazen literary charlatan, Richard Gere gives one of the best performances of his career. Working from a smart, witty script by William Wheeler (adapted from Irving’s memoir, also called “The Hoax”) and some uncharacteristically sentiment-free direction from Lasse Hallstrm, the actor projects charm and chutzpah, but also the absolute fear that must have been coursing through Irving’s veins.

Digging himself deeper and deeper into a pit of falsehoods and fabrication, Irving rushed here and yon engaged in legitimate research, and illegitimate research, too (i.e., stealing the unpublished accounts of a Hughes’ confidante).

Irving’s wife, Edith (Marcia Gay Harden), an artist with a European accent and passport (all the better to open a Swiss bank account with) was likewise party to this epic fraud. One of the things “The Hoax” does so well is show how Irving not only sold his publishers a bill of goods, he sold his friend, and his spouse, an equally wild and impudent story. His self-delusion became theirs.

In its own twisted way, “The Hoax” is classic American Dream corn: Believe in yourself, follow your dream, go for the gold.

Hallstrm and crew capture the seemingly simpler times of the early ’70s with dead-on costumes, coifs and cars (and pop music). Julie Delpy shows up as Irving’s mistress – jet-setting actress Nina Van Pallandt – and Hope Davis plays Irving’s editor, who stands by her man until the bitter end.

That end, which is also how “The Hoax” begins (yes, this publishing world movie is book-ended), features an apocryphal but metaphorically brilliant Irving stunt. Without giving too much away: It involves the scheduled appearance of a key player in these shenanigans, the rental of a helicopter and the urgent last-minute refurnishing of the executive floors of a Manhattan skyscraper.

“The Hoax” makes the fakery of disgraced writers Jayson Blair, James Frey and Stephen Glass seem puny by comparison. Irving was the grand master, and Gere’s portrait and Hallstrm’s movie suggest why: He almost bought his own story, believed his own outrageous pack of lies.