With "Six Degrees of Separation," the performances are the thing.

This adaptation by John Guare of his award-winning play boasts some witty moments and is well-directed by Fred Schepisi ("A Cry in the Dark," "The Russia House"), but it would never work without the right players in the three lead roles.

Fortunately, Donald Sutherland, Will Smith and especially Stockard Channing (reprising her Broadway character) are more than up to the task, giving a real boost to what is otherwise a rather simplistic yarn.

Channing and Sutherland are Ouisa and Flan Kittredge, a wealthy couple living in a Fifth Avenue apartment in New York City, where they fancy themselves liberals and the elite of their uppercrust social circle.

So, when Paul, a young black man (Will Smith), shows up bleeding on their doorstep, they take him in immediately. Claiming to be a college friend of their children, Paul explains that he was mugged across the street in Central Park.

The Kittredges see to his wound, and in return, Paul fixes them a fancy dinner, regaling them with stories of his life in Hollywood. Paul claims to be the son of Sidney Poitier — and he even offers to get the Kittredges roles as extras in his father's new movie version of the musical "Cats."

Eventually, of course, Ouisa and Flan tip to the idea that they've been had — when Paul makes the mistake of picking up a gay lover and bringing him to their home.

We see all of this in flashback form, as they relate the story to their friends. And to their surprise, they learn that their friends have also had an encounter with Paul — very similar to their own.

The police don't want to intervene since there was no crime committed, and though the Kittredges look upon the incident as high adventure, their spoiled children see it as yet further proof that Ouisa and Flan are out-of-touch hypocrites.

Most of these characters are not particularly sympathetic, with the possible exceptions of Ouisa and Paul, who develop an oddly affectionate relationship. Unfortunately, this latter element is not fleshed out very well, and ultimately, the film seems like a pop-psychology theatrical conceit.

Still, there are those wonderful performances by the lead players — and especially Channing, who has been underused or misused most of her film career — and they make it fairly enjoyable entertainment.

"Six Degrees of Separation" — the title refers to the claim by Ouisa that everyone in the world is separated by no more than six people — is rated R, primarily for language, with some violence, nudity and offscreen sex.