IT IS lunchtime in New York. Four actors are seated around a table at Sardi's -- mixed couples who represent a something like a century of collective experience. They are:

michael Higgins, known in the trade as an "actor's actor," winner of two Obies (most recently for his role in David Mamet's "Reunion") and widely acclaimed for his performances in such plays as "Equus" and "Whose Life Is It Anyway?" He is the quiet member of the party.

Julie Harris, who has won five Tony awards (most recently for "The Belle of Amherst") and almost every other award that can be given to an American actress. At the moment, she is thinking about the beach plums near her home on Cape Cod, and how she is always reminded of Lady Macbeth when she cooks them into jelly because they turn her hands blood-red.

Geraldine Page, who also has a closetful of awards and has recently been elected to the Theater Hall of Fame: "Michael and I did this play already, in the old days," she is saying. "We call them the newcomers."

Rip Torn, who has won awards for directing as well as acting in everything from Strindbert to "The Honest to God Snozzola," who has played Walt Whitman and a country blues singer and tragic rulers from Richard III to Richard Nixon. Torn is a newcomer not only to the lunch (where he arrived late and slightly breathless) but to "Mixed Couples," which Page and Higgins did last year in an earlier version called "Slightly Delayed."

They are four-fifths of the cast of James Prideaux's "Mixed Couples," a comedy about two couples who meet by accident at an airport. The play is in its third week of rehearsals and almost ready to move to the Kennedy Center. "We have only two previews in Washington before we open on the 20th," Page is saying. "That will just barely give us time to learn how to open and close the doors."

"There's only one door," says Harris optimistically. "It's an airplane hangar."

In "Mixed Couples," Harris is married to Torn, who is married to Geraldine Page offstage. Page is married to Higgins onstage -- as they were last year in an earlier version of the play called "Slightly Delayed."

Page reminisces about times when she and her husband have been married on the stage or screen -- including one occasion when Rip Torn was put in a compromising position with Julie Harris: "We were married in Strindberg's 'Creditors,' and then there was that picture we were all in together."

"'You're a Big Boy Now,'" Harris says. "It was Francis Ford Coppola's first film."

"I was married to Rip and Julie was our landlady," Page recalls. "Rip was a librarian -- a curator of rare books, and he had one line that I love: 'You're getting lint on the Gutenberg Bible.' You have to see it for the scene where Julie and Rip get caught in the pornography room of the library. There was something special about the way he came staggering out."

Rip Torn shows no concern at the way "Mixed Couples" has mixed the Torn-Page couple. "I wasn't the type for that role, and I like the one I have. In this one, all I have to do is smoke cigars." He is, in fact, puffing on a cigar as he speaks.

"At the beginning of rehearsals, they used to supply me with El Cheapos -- it was like smoking a grapevine. They're finally getting me some good ones. These are very mild." He takes another puff. He is rehearsing. He does not usually smoke cigars.

He smokes cigars the way he plays the piano -- as part of an acting job. In "Daughter of Silence," he played a pianist and had to perform a Chopin nocturne onstage. "One music critic in Philadelphia listened to it seriously and said that it was well-done except for one triplet figure. I used to be able to play that nocturne long after the play ended, but I don't know whether I could today. For 'Payday,' I learned to play the guitar and sing three songs -- but that's my total guitar and song repertoire."

This reminds him of an old tradition in the theater: "Actors were expected to 'double in brass,' to play a horn in the band when they weren't needed as actors. I suppose that smoking a cigar is easier."

The cigar is a prop from rehearsal. Ordinarily, Torn doesn't carry any part of the role with him when he leaves the stage -- and neither do the others. "I remember when we were doing 'Marathon '33,'" says Harris, "and June Allyson said, 'wouldn't it be terrific to have a real dance marathon before we start.' I was horrified."

"You don't have to go out and kill a king before you can do Lady Macbeth," Page says, "but you never know when an experience may be useful. An actor's mind is like a vacuum cleaner. We sweep up experiences and set them apart, perhaps for years, until we may need them. Sometimes we do it consciously, but mostly its unconscious or sub-unconscious."

"It can be hard work," says Torn. "I remember when I was cast in 'Desire Under the Elms,' and I wondered what they were doing putting a Texan in a New England role. So I went up to New Hampshire and taped a hunting guide so I could learn his accent. Then they went and cast Texans in two other roles."

"Ayeh," says Higgins. He means "yes," but he learned this New England variant once for a Eugene O'Neill role and later made a study of the different American forms of the word. He starts running through his collection: "Yep, yeah, ayeh," and Torn offers a new contribution: "In Montana, they say, 'You betcha.'"

Throughout the conversation, the players are somewhat coy in talking about the play. "It happens in an airport in New Jersey," says Page helpfully. "Two couples happen to meet and as they start talking, little facts about the past begin to emerge. It's a comedy, basically, but it is also a sort of mystery because there are things in it that are unknown at the beginning -- to the audience and to people in the play. I guess we shouldn't talk about the plot too much."

"Mixed Couples" is set in 1927.The show is, in some ways, about the nature of reality and the mutability of memory. "It's a comedy, but it has a sort of 'rashomon' element in it -- conflicting memories," Harris offers. "We knew one another when we were young. Now, we're middle-aged and we meet in this airport while our flight is delayed, and things from the past keep slipping out."

For Higgins, "Mixed Couples" is a change of pace and he's enjoying it. "It's not my first comedy," he says, "but I do play a lot of heavy drama -- 'Macbeth,' 'Hamlet,' 'Antony and Cleopatra,' for example -- and for contemporary plays, 'Equus' or 'Whose Life Is It Anyway?' Look at my credits and you wouldn't think I liked comedy."

The "Mixed Couples" cast has phoned ahead to order food because rehearsals are on a very tight schedule; only one hour is allowed for lunch. "I usually bring my lunch and eat it at the studio," says Harris. "An outing like this is really a treat for us."

She looks around the dining room, reminiscing: "I can remember my first lunch here, right after I made my debut on Broadway. Florence Reed invited me -- 'You're such a marvelous child,' she said." Harris' voice gets deeper, throaty, and the accent changes, remembering the old actress' voice. "She brought two of her friends, and they were all wearing white gloves," her hand reaches to her wrist to tug off an imaginary glove. "Nobody wears white gloves in New York any more."