ELI WALLACH and Anne Jackson, who are married to the theater and to each other, sit on a couch in front of a mock-Gothic fireplace in the Kennedy Center Green Room, discussing theater couples. They're entitled - behind them are five Kennedy Center theater posters for plays they have starred in here. Miss Jackson is talking about the fact that as a couple they tend to protect each other on stage: ``We both have been in the theater long enough to know where the values are, and sometimes if a director doesn't see it the way we do, we defer.
``We do it with other actors, as well,'' she says. ``But when there are just the two of us, we kind of protect each other against bad lighting or staging we don't particularly like. I'm very bossy, too, unfortunately, amn't I?''
Mr. Wallach says, ``I'm afraid to answer that one.'' They both laugh.
They have done nearly 20 roles together, ranging from plays like their favorite ``The Waltz of the Toreadors'' and ``Twice Around the Park'' to movies such as ``How to Save a Marriage and Ruin Your Life'' and ``The Tiger Makes Out.''
They met nearly 40 years ago in an Off Broadway production of Tennessee Williams's ``This Property is Condemned.''
They've worked together on stage whenever possible since then.
Wallach says, ``I consider it a plus to find a project that brings us together. We're not restricted, though, to only working together.
``The Lunts [Alfred Lunt and Lynn Fontanne] made a pact that they would only act together - until the last years of their lives. But our pact has never been that we'd only act together. It proscribes your area of experience. It's difficult to find a play that's equally balanced. And fun.''
Wallach, who appears as a psychiatrist in the new Barbra Streisand film ``Nuts,'' is dressed in civvies: sneakers, gray jacket, pink shirt, tan trousers. He is surprisingly beamish for a guy who's played some real heavies - as in ``The Magnificent Seven'' - a silver-haired gent with a kind face and a soft voice.
Speaking of the Lunts and other devoted theatrical couples - like Jessica Tandy and Hume Cronyn, Frederic March and Florence Eldridge - Wallach says, ``I think any creative relationship is a plus. It's so wonderful to do something together.''
Jackson chimes in, ``I know that because people had worked together, audiences would say especially about Lunt and Fontanne that he would have his followers, and she would have hers. I don't think the same thing has happened about Jesse and Hume, although it may have.
``But there's always the danger when you are a team, or a couple, to either be lumped together or to have critics favor one and not the other. So one just has to take their chances with that.''
But that doesn't seem to have happened with Wallach and Jackson.
``No,'' she says, ``we haven't had that problem. I also think the fact that we didn't set ourselves up as a team, that we acted independently - and then when the opportunity came, we acted together - kept us away from the critics being so severe on the team.''
Jackson is a petite woman with a bubbly pile of auburn curls and a pert face. She is definitely not dressed to make a dramatic entrance for this interview: aqua sweater, denim skirt, navy wedgies.
Her appearance in the CBS sitcom ``Everything's Relative'' ended abruptly last fall when the network canceled the series, in which she played a career woman with two bachelor sons.
As an actress, she has won an Obie for her role in ``The Typist and the Tiger'' and Tony nominations for her performance in ``Oh, Men! Oh, Women!'' and Tennessee Williams's ``Summer and Smoke.'' Wallach, who is famous for his Williams roles, won Tony, Theater World, and Donaldson Awards for his performance in Williams's ``The Rose Tattoo.''
In addition to their theatrical collaborations, Eli Wallach and Anne Jackson are the parents of two daughters and a son, and grandparents of a one-year-old, Jason Vincent Wallach, by their son Peter.
Wallach: ``Anne was the first Jean Arthur standby in `Peter Pan,' and when she got pregnant...'' Jackson joins in, ``...I was grounded.''
Wallach finishes, ``The doctor said she couldn't fly, so we named him Peter.''