It's clear from the beginning that "The Supporting Cast," George Furth's new comedy at the Eisenhower Theater, does not believe in its own premise. So half the entertainment for the evening consists of waiting to see if the characters will catch on.

They don't: It's a futile wait. There is still, however, the other half, which is watching the characters walk splat! into a glass door, which they keep forgetting is there. That's the better part of the evening.

The premise is the behind every famous person there's a little woman, and she -- in one case, he -- is just as important as the celebrity is; that she is, in fact, a heroine for nurturing the star and making that stardom possible. Four such culture heroes, all from New York, have been assembled at the Malibu house of a fifth -- Hope Lange as the daughter, ex-wife and current wife of (respectively) a governor, a golf champion and a Pulitzer Prize-winning historian. She has written a book about them, a fact she is springing on them during a delicatessen lunch she's had flown in from New York.

The book shares its title and theme with the play, and this heroine spends the whole evening trying to get this idea across to the others, while they persist in being insulted because they're characterized as fools.

Their position would have some dignity of the original premise were true. But it's obvious to everyone except the playwright and book author that they all believe, deep in their hearts, that the chief thing in life is being famous, and that this book, with its unprecedented pre-publication success, is going to do it for them. For those who have spent their lives tending the sacred flame, they certainly are slow to grasp its basic law: That it doesn't matter what people write about you so long as they spell your name correctly.

These people are:

Sandy Dennis,in her hysterical act (a good act, but one we've all seen by now) as a congressman's estranged wife, looking, in layers of draped remmants, unlike any congressman's wife this town has ever seen. Her heroism has consisted of making public scenes and refusing to recognize her husband's desire to terminate the marriage.

Jack Gilford, another good comic actor, as the fusty husband of a palywright, whose heroism consists of nagging their hotel to make the beds the way his wife likes beds made.

Betty Garrett, a valiant tropper, as the mother of a musician, her heroism consisting of having embarrassed him on national television.

Joyce Van Patten, managing to put some appeal into the awful role of a movie star's wife, whose nobility consists of following him everywhere, with their children, because she knows that if she lets him out of her sight he will find someone else.

The setting for the gathering of this group of second-rate characters is constantly being threatened by fire, earthquake and frozen traffic. At no time does this suggest to anyone in the play that celebritydom is not the most potent marvel of the universe.

THE SUPPORTING CAST -- At the Kennedy Center's Eisenhower Theater through July 25.