The tricky thing about the truth is that it can bite you on the ass.

The brutal side of honesty takes its toll in Closer, Mike Nichols’ film adaptation of Patrick Marber’s acclaimed play about four people who stick their bums out for a big ol’ chomping.

With an all-star cast that’s easy on the eyes (who’d kick Jude Law, Clive Owen, Natalie Portman or Julia Roberts out of bed?), Closer is a love story void of sweetness — a too-bitter examination of a sex rectangle born of jealousy, lies and the lying liars who tell them.

A chance meeting pairs Dan (Law), an obituary-page writer, with Alice (Portman), an American stripper with a seedy past who becomes fodder for Dan’s first novel.

Flash forward a couple of years, and Dan, still with Alice, inexplicably makes out with Anna (Roberts), the photographer taking his photo for the novel’s jacket.

Alice discovers the liaison, but looks the other way. Meanwhile, Dan’s obsession with Anna swells. To toy with her, Dan directs Larry (Owen), a doctor with a penchant for sex chat rooms and strip clubs, toward Anna, but the joke is on Dan when the two actually hit it off. A few rounds of infidelity and revenge sex lead to more couplings, uncouplings, feuds and reunions. It’s a messy tangle of sex and lies.

Owen, the least famous of the bunch, stands out as Larry. On the surface, Larry would seem the least likable, most brutish character; but Owen (who played Larry in the original London stage production) imports a rawness, sensitivity and uninhibited passion. As much as Larry is a cad, he also has the most emotional integrity — thanks mostly to Owen’s rendering.

Owen owns two of the film’s funniest and most striking scenes. In one, he’s hilariously worked up while getting off in an online sexcapade with Dan, who’s posing as a woman. In the other scene, Owen displays vulnerability after a jilted Larry stumbles into the sex club where a jilted Alice works. Portman’s much-buzzed strip scene is seductive, but overpowered by Owen’s commanding emotional outpouring.

On the other hand, Roberts, who is the most famous (and likely highest-paid), remains confined to her usual extremely narrow emotional range. She can play cute, coy and charmed, and really pissed off, but delves no deeper.

What’s more, this is a film about sexual politics that flashes more talk than flesh. Frankly, sex talk from “America’s sweetheart,” the woman who brought us the hooker Cinderella (Pretty Woman), is decidedly unsexy. Hearing Roberts detail how often she came, got it from behind and sucked cock is like hearing your best friend’s aunt talk dirty. Eew. Eew. Eew.

But Closer has bigger flaws. Nichols (The Graduate) knows very well how to milk a sound track and consistently extracts the best from his stars. But even his magic fails this film; the story is mired in such extreme heartache and pain, with so little joy, that it becomes hardly bearable. With one dramatic blow-up after another, each scene plays as if it were the climax — leaving one to ask, where’s the foreplay?

Clare Pfeiffer Ramsey writes about film for Metro Times. E-mail