In I Love You Phillip Morris (no relation to the tobacco company), writer-directors Glenn Ficarra and John Requa pull off something that until now hasn’t been done in mainstream American cinema: A story where the two main characters are men in love with each other, and where that love is just a matter of fact, and not what the film is about.

Based on the barely believable life of a part-genius, part-hapless con man named Steven Russell (Jim Carrey), this film finds its focus on the fuzzy lines that separate identity, perception and deception, questioning how much we can ever know about a person, beyond what they themselves want us to know, and what we want to believe about them.

Thanks in no small part to the inimitable gifts of Carrey, who delivers one of the more inspired performances of his career, the end result is a tragicomic romp that at its best is beguiling, and only loses momentum when its main character suffers from that ironic bane of real life: getting what he wants.

For Steven, the wanting starts early. When he is just a boy, his parents inform him that he is adopted, and that his biological mother traded him for a bag of cash in a hospital parking lot. Crushed, Steven vows from then on to be the best person he can be. As an adult, he becomes a small town police officerand plays the organ at church on Sundays. He has a daughter who dotes on him and a loving, pretty wife named Debbie (Leslie Mann) whom he makes love to with his pajamas on.

We then learn that Steven is not to be trusted: He tells Debbie that he has discovered the identity of his biological mother, and that he only became a police officer for the access to records.

When he ends up at his mother’s door, in uniform, she reflexively denies any knowledge of his existence. Dejected, Steven skulks back to his patrol car with her welcome mat in his hands, a deft comic touch to a heartbreaking moment, a strategy that Ficarra and Requa use with great success throughout the film.

Thrown off the rails of predictable small town life, Steven spins off into the unknown, and the movie unfolds in a rapid succession of revelations: He quits the force, moves his family to Texas, is involved in an almost deadly car accident, after which he sets out to live his life as his true self – no more lies.

He finally comes out to his family that he gay, and his true self takes him to mid-80s Miami, where he embraces a flamboyant lifestyle that his job as a mid-level corporate salesman can’t possibly pay for. So begins his life of crime, engaging in types of “victimless” fraud (insurance, credit card, etc.).

This is where the film really gets fun: As we watch Steven spin his web of deceptions, it is clear that after living a lie for so many years that he can make anyone believe he is just about anything.

What he can’t seem to do is cover his tracks, and his next stop takes him to a Texas penitentiary, which is where he meets the love of his life, a soft-spoken, blue-eyed Phillip Morris (Ewan Macgregor). A jailhouse romance ensues, and it is a credit to the actors and directors that the relationship feels not only natural, but real.

This is, however, where the film slows: Now that we have some idea of who Steven is, and can see that he has found the love and acceptance he spent his whole life seeking, it feels like the story loses its pull. Steven, for his part, makes up for it by pushing. Though he promises Phillip that he will keep things legal, he can’t resist what comes so easily, conducting a string of cons that are increasingly audacious, genius and downright insane. From here the film stays entertaining to the end, and watching Steven pull off a final, nearly fatal ruse is in itself worth the price of admission.

Adapted from a book by former Houston Chronicle reporter Steve McVicker, Phillip Morris marks the directorial debut of Ficarra and Requa (whose previous credits include scripting Bad Santa), and they have done well to take a story that is not inherently cinematic and turn it into what is ultimately a provocative, jaw-dropping spectacle.

Ficarra and Requa employ shots of drifting clouds as a repeated motif in Phillip Morris, and fittingly, we can make of them what we want. What stuck with me, long after the credits rolled, was that people, like clouds, are mutable bodies composed of immutable elements, and no matter what shape we see in them, their essence remains unchangeable.

I Love You Phillip Morris (3) Directed by John Requa, Glenn Ficarra • Starring Jim Carrey, Ewan Macgregor. • Rated R, 98 min. • At Osio Cinemas.