ANN-MARGRET MEETS UP WITH THE ‘OTHER WOMAN’ : By CHARLES CHAMPLIN, <i> Times Arts Editor</i>

On fortunate afternoons a quarter-century ago, a traffic-stopping young woman, still in her teens, would pop into the Life office to see Shana Alexander, who was doing a story about her for the magazine. She was known then, as now, simply as Ann-Margret; she was not long out of Northwestern and had been discovered by and hired as a sort of singing sidekick for his Las Vegas act by George Burns.

Alexander had presciently decided that Ann-Margret might well be going places, and the reverent hush that fell over the office during the visitations hinted that Alexander was not wrong. But I’m not sure any of us would have predicted that this uncommonly attractive young woman--a paradoxical mixture of innocence and sexiness--would have become something of an institution, and such an impressive dramatic actress.

But Mike Nichols saw her in a steamy 1964 black-and-white melodrama called “Kitten With a Whip,” in which she played a reform school escapee, and asked her to fly to New York and read for a part in “Carnal Knowledge,” which he and Jules Feiffer were preparing.

She did, and then agreed to a screen test, and was sitting alone in her hotel in a cold sweat, awaiting word, when a messenger arrived bearing champagne and flowers and a note that read “I love you. Jules loves you. You have a job. Mike.” It is framed and hangs on the wall of her living room in her home off Benedict Canyon high above Beverly Hills. She pointed it out to a visitor earlier this week.

She won an Academy Award nomination for that role, as a woman who keeps choosing the wrong men, and who is ever more despairing at being perceived and used merely as a sexual object. The portrayal had a tough, truthful power that still reverberates in memory.

She has done much else since, including a strongly affecting performance in a television film called “Who Will Love My Children?,” about an Iowa farm woman dying of cancer, and another as Stella in the television version of “A Streetcar Named Desire,” a role she says Tennessee Williams had hoped she would do but did not live to see.

Just now she is playing the “other woman,” who Gene Hackman falls in love with and leaves his wife for, in Bud Yorkin’s “Twice in a Lifetime.” She had auditioned for Yorkin and Norman Lear when she was 18 and had just finished her Las Vegas stint with Burns.

“They were shooting ‘Come Blow Your Horn’ and I sang for them in their office.” Nothing happened at the moment, but in 1962 she appeared on an Andy Williams special for them.

Yorkin sent her the “Twice in a Lifetime” script when she and husband-manager Roger Smith were partway through a year’s sabbatical. Smith has myasthenia gravis, presently mercifully in remission, and she had been working without pause.

“I’d done three films in a row and two concert tours. In fact, I’d finished shooting ‘Streetcar’ and four days later I opened in San Francisco at the Golden Gate Theater, starting a national concert tour. After that, we were going to have a year for ourselves.” They’d had 10 quiet months when Yorkin sent the script to them in Aspen.

Fond of Yorkin but not eager to interrupt the holiday, she lifted the Colin Welland script and said, “ ‘Boy, I hope it’s not too terrific.’ But it was, and I said, ‘Roger, you’d better read this.’ ”

Like the part in “Carnal Knowledge,” the role goes against the leading-lady image. “She’s the other woman, and if you don’t like the other woman, you’re not about to like the movie. In fact, people would’ve thrown stones at the screen if they’d hated her.

“But this is 1986, and I think it’s an honest look at marriage and divorce as they are now. Nobody does anything wrong. The other woman doesn’t try to break up the marriage--it’s been disintegrating for 10 years. She’s had a nice marriage and her husband’s just died. She’s not ready to start looking for somebody.

“What does she see in him? He’s kind, he’s shy, he’s polite, he has a sense of humor. The laughter is very important for them. It’s honest and it’s basic, basic, basic. There are lines in it that make me want to cry when I think about them.

“When I was in school you were married for 30 years and nobody got divorced. It wasn’t done. Now, almost every other marriage ends in divorce, doesn’t it? What I liked about ‘Twice in a Lifetime’ was that we all know people like that, people in that kind of pain.”

She and Smith have been married, very happily, for 18 years, and have lived in their hilltop house for 18 years, since he received custody of his three now-grown children and they needed more room. They have three grandchildren.

By now, she has done 39 films, from very heavy to very light. (She recalls with particular deep pleasure doing Jezebel Desire in “The Cheap Detective.”)

She has won over most of the critics who might have been dubious about a sexy singer and dancer becoming a versatile dramatic actress. There have been some other pleasant rewards. Last summer, one of the daughters of the woman she played in “Who Will Love My Children?” invited her to be the grand marshal of the 4th of July parade in Storm Lake, Iowa, and she was.

She had not performed musically for nearly three years, until she sang “I’ve Got a Crush on You” for George Burns’ 90th-birthday television special. They have both come a long way since their Vegas days.