There are typically only two means through which ‘gay' movies make it into the American mainstream. The first is through prestige and ‘worthiness'. The excellent Brokeback Mountain resides here, but that it lost the Academy Award for Best Picture to racial-tension potboiler Crash was more a statement about America's guilty conscience on the subject than of which film deserved it more.

The second is to portray homosexuality as a joke. This has proven the more financially viable route Stateside, with the lamentable I Now Pronounce You Chuck & Larry taking a lot more at the box office than the award-winning ‘gay Western'. While we're hardly living in the dark ages, there's no denying that cinema-goers aren't entirely comfortable with this supposed taboo just yet.

Enter I Love You Phillip Morris, which crosses between both and has thus had a troubled path to cinemas. Indeed, at one stage it looked likely that the film would go straight to DVD. The subject of the studios' reticence is Steven Russell, played by Jim Carrey, a Texan cop who comes out of the closet in the wake of a near-fatal traffic accident.

Steven then ups and leaves his happy (and more challengingly, Christian) family to live in excess with his boyfriend Jimmy, becoming a conman to fund his expensive new lifestyle. When the law catches up with him, Steven is sent to prison, where he meets Phillip Morris, played by Ewan McGregor. The mild-mannered Phillip has his head turned by Steven, and the two spend the next few years flitting in and out of jail in their efforts to be together.

Jim Carrey has had hits and misses in both his comedic and dramatic roles, and I'm pleased to report that his work in I Love You Phillip Morris counts as a hit. He strikes just the right balance, in a marriage of his more over-the-top acting (Liar Liar), and his more restrained and dramatic performances (The Truman Show).

While Ewan McGregor amiably continues to get his career back on track now he's finished faffing about with George Lucas and Dan Brown, and Leslie Mann makes a brief but memorable impression as Steven's befuddled ex-wife, it's really Carrey's show. He's surprisingly intense in places, but he still has better comic timing than most actors working today, and he's never any less than compelling here.

The mix of comedy and drama in the script itself is often unsettling, but you can really expect nothing less from Glenn Ficarra and John Requa, the writers of Bad Santa.

At key points of the film, you'll have the rug pulled out from underneath you in much the same way as the victims of Steven's cons. It can lull you into a false sense of poignancy and then make you laugh out loud. It can have you chuckling away and then emotionally sucker-punch you. Whatever your thoughts on homosexuality, this isn't a film you can relax into.

The ‘gay thing', as I've heard it referred to by more uncomfortable viewers than I, is never really the punchline to any of the jokes, and the film is better for it. Only one scene stood out as a contrivance. An escape attempt by Steven leads him to procure some clothes from another inmate. Apparently, all he could get was a leopard-print mesh vest and some red hotpants. Either he's the least resourceful inmate ever, or the writers really wanted to put Carrey in that kind of sight gag.

Besides that, the only other off-putting aspect of the film was the appearance of Brennan Brown, better known to cinema fans as Mr. Dresden, the mind-addled film producer from those Orange ads before the film begins. Just as in last year's State Of Play, it's really jarring to see him doing anything serious when you saw him just a short while before, trying to get Danny Glover to promote ‘Dial Hard'.

On the whole, I Love You Phillip Morris is funny as hell, and in several instances, it's really profound. Ficarra and Requa never shoehorn homosexuality into any of the parodic tropes you've seen elsewhere, and it's just a very well-written and likable comedy.

I don't doubt that The Bounty Hunter is a more likely romcom prospect this weekend, but shame on the American distributors, anyway. In this case, audiences should choose Ewan McGregor as the lead love interest over Jennifer Aniston any day.