Patrick Stewart, left, and R.R. Knight. Photo: Carol Rosegg

Insecurity, distrust, rivalry, frustration, and fear — all the qualities that make acting a questionably/arguably glamorous profession are affectionately and humorously exploited in David Mamet’s 1977 comedy “A Life in the Theater.” As this is the first Broadway production of this play that had a long and successful run Off-Broadway 33 years ago, it is good to report that the cast of two (plus assorted stage hands) — Patrick Stewart as Robert and T. R. Knight as John — is bringing to it an air of importance that it would not ordinarily warrant.

An ex-actor himself, Mamet knows how to infiltrate the deeper recesses of an actor’s motivations and expose with acute delicacy and accuracy the darker and more personal aspects of the profession. An overriding and deeply felt love for these people and a fine farcical style give his play an immensely appealing quality. Neil Pepe, who capably directed Mamet’s “Speed the Plow,” is undoubtedly in league with the Mametian style, be it comedy or drama, and correspondingly stages this play with assertive know-how.

Robert, the older actor (Stewart) and John, the younger actor (Knight) share a dressing room in a resident repertory company. They also share their tension and stress-related anxieties in regard to their joint performances. At times supportive, other times bitchy and cruel, the actors banter back and forth in the privacy of their backstage arena. Critical of each other even as they are aware of each other’s vulnerability, they throw a slew of timid innuendos as well as some telling punches at each other. All of this while also facing their self-absorbed reflections in their own mirrors.

With outrageous and high-toned pomposity, Robert instructs his young initiate on the realities of life in the theater and in one early scene asks Robert, with incredible gall and condescension, “In our scene together tonight, could you possibly do less?” “Do less what,” John asks, creating a near avalanche of defensive rhetoric that establishes the tone and substance for the evening.

Watching the actors pick at each other off-stage prepares those of us (the audience) who have been more or less eavesdropping up to now for a series of short, hilariously stereotyped scenes from some obviously dreadful fictional plays. That they may also remind you of the vaudeville-like sketches we used to see in the Carol Burnett TV variety show is meant as a compliment. These are performed quite often, but not to the detriment of the comedic impact, with the actors’ backs to us as they face an imaginary audience. A hoity-toity penthouse melodrama, two sailors adrift on an ocean-battered dingy, a Pinter-esque bore, and probably one of the funniest scenes you’ll ever see of two surgeons forgetting their lines and ad-libbing while performing an operation certainly had me, as well as the audience on the night I attended, laughing heartily.

The witty dialogue lives up to the conceits that the play purports. Whether it will win you over as it did me will depend on your feelings for the theater and for the people who make it live. If both parts are nicely realized by Mamet’s poetic and intuitively felt truths about what he knows from firsthand experience, they are enhanced by the nicely contrasted personalities of the two stars.

Stewart, whose stature and fame comes as much from his roles in classical theater as it does in films and TV, may not be as vain, colorful, or obsessed/possessed by his character as the role might allow, but he has a sly way of making Robert’s eccentricities both pretentious and poignant. And allow me to quote from Stewart’s bio in the Playbill: “Appearing as Robert, I am remembering three leading actors who allowed a greenhorn 19-year-old to share their dressing room at different times at the Sheffield Repertory Theater, England: Victor Lucas, Philip Stone, and George Wearing. Without knowing it, they taught and inspired me. They are all gone but I remember them with affection and gratitude.” Stewart’s performance, a model of unaffected affectation, certainly resonates with this memory.

Stewart’s restrained eccentricities are amusingly tempered to balance Knight’s youthful zest and impatience. Although Knight’s popularity is probably due to his work as a regular in the TV series “Grey’s Anatomy,” his stage appearances over the past few years (“Noises Off,” “Tartuffe”) have also proved him a fine and accomplished actor. There is no doubt that he is as much in command of the stage at any given time as is his more mature partner. The great set designer Santo Loquasto has contributed the impressive physical production that engages an extraordinary number of props. These not only make their own broad swipes at the profession but are also essential elements in the broad sweep of the plays within the play. ***

“A Life in the Theater,” through Sunday, January 2, Gerald Schoenfeld Theater, 236 West 45th Street. $76.50 to $251.50. 212-239-2600.