HANG ONTO YOURSELF. I watched Boston Legal this week. Most weeks I catch at least a little of it. It's a horrible, horrible show, the apotheosis of David E. Kelley's lurid vision of professional life as an endless series of jacked-up and frequently absurd job crises, the tension of which is inevitably relieved by sexual intrigue (also in an endless series, and jacked-up, and frequently absurd). Most of the players are attractive young people who can barely get their chiseled jaws around the preposterous dialogue.

But Boston Legal stars James Spader and William Shatner, and they make a fascinating spectacle in this shabby little arena. From the beginning, they have seemed to inhabit a different universe from all the other characters. They float through their scenes like 19th-century royals after a good lunch at Maxim's, self-satisfied and serene. They are dimly aware of the other characters' needs and desires, and sometimes are inclined to indulge them for reasons of appetite similar to those that animate the other characters -- professional honor or glory, morality, and sex. But where the other performers sweat this stuff, granting it as much importance as I believe the audience is meant to, Spader and Shatner feel the pangs of motivation as one might feel an urge to scratch or stretch, and react to them with refreshing naturalness and self-possession.

This makes them stand out, and reveals a mystery of the performer's art. Acting is a cooperative venture; even monologuists must engage the camera or the audience, while most players also have to evidence relationships with other players. So the actor has to concentrate on people as well as lines, blocking, and the director's orchestration. Maintaining this divided consciousness is a key part of the job, and when an actor says "I really felt it tonight," he is (usually without noticing) celebrating the fact that he felt it while doing everything else he had to do. (Interestingly, Pauline Kael relates that Orson Welles had just this sort of epiphany, which seems to have been rare for him, during the solo in Citizen Kane in which he wordlessly smashes up a room.)

Good actors can handle all that, but great ones know that there is another focus of concentration that needs to be maintained: the concentration on oneself as a character. The famous hams, of course, concentrate on themselves, period, which is actually almost as good. I thought of this while watching John O'Hurley -- yes, Peterman! -- play Billy Flynn recently in Chicago. He wasn't quite what I had in mind, and his schtick usually tires me, but he seemed so perfectly comfortable with himself and his "That's right, Elaine, the white lady -- yam-yam!" readings that he made me comfortable, too, and pulled me over my general objections.

This is why stunt casting is seldom totally disastrous: assuming the player has not lost the nerve that made him or her a celebrity, that boldness in self-presentation will read from the cheap seats as well as a journeyman actor's conscientious characterization.

(This self-regard is not the same thing, of course, as self-consciousness; self-consciousness will make even a great spirit awkward; the self-regarding man could walk into a scene covered with shit and, after perhaps a brief word of explanation for the stench -- offered for your benefit, not his -- go on as if nothing untoward had happened.)

I think Spader and Shatner have a little more on the ball than O'Hurley, but while their characters have a few shades to them, it is their extreme comfort with themselves that makes them galvanic. The relative slightness of their interest in other people is perhaps a little hammy, but certainly not offensive -- if you were this fascinating person, wouldn't you be more interested in yourself, too?

That Spader and Shatner have one another to re-enforce this routine just exponentiates the effect; I especially enjoy the coda of each show, where they sit out on the balcony with drinks and cigars and stare out onto the skyline while talking out their days -- parallel egos taking a moment to take mutual pleasure in their singularities.

For further reference, see Jose Ferrer in Enter Laughing, or Errol Flynn in anything. But I'm sure you can think of other examples.