Folks who tune in to the popular CBS sitcom Newhart each week expect certain things: They expect that, whatever the situation, innkeeper Dick Loudon (Bob Newhart) will raise his eyebrows clear up to his receding hairline and try to make sense of it; that, try as he might, dim-witted handyman George (Tom Poston) won't be able to make sense of it; that unless it involves her, the Stratford Inn's self-centered yupcake housekeeper, Stephanie (Julia Duffy), won't bother to make sense of it; that her self-centered yuppie husband, Michael (Peter Scolari), will try to make dollars and cents of it.

And when it comes to Dick's perky wife, Joanna (Mary Frann), viewers also know what to expect: that she is capable of no greater lapse than forgetting to fluff the bathroom towels.

Well, Frann's fans are in for a jolt. In the TV movie Single Women, Married Men, airing this week on CBS, her problems are considerably more weighty than the incompetence of the Stratford's hired help and the frequent interruptions by the backward backwoods brothers Larry, Darryl and Darryl.

Loosely based on the experiences of Dr. JoAnn Bitner (see following story, p. 116), the movie describes the San Diego psychotherapist's work with a support group for unattached women who find themselves irresistibly drawn to other women's husbands. Frann plays Pat Michaels, a woman who becomes pregnant and is abandoned by her married lover. As Newhart's Larry might say, "Lord, Miss Joanna, what a mess you've got yourself into now."

Actually, Frann, 46, couldn't be happier about playing a character whose life is in even worse shape than Larry's hair. "I'd love to come apart at the seams on Newhart," she says. "That's something I'm always saying: 'Get me in trouble.' " Bob himself can sympathize; placidity earns little limelight on Newhart. "We can't all be acting crazy," he says. "Mary and I are kind of the glue that holds the show together. Mary's very underrated in terms of her contribution to the show, because often she and I just have to react to the weirdness that's going on around us."

Newhart isn't exactly Frann's first exposure to weirdness. One of her early attempts at breaking into show business included playing a cheerleader named Polly Perk who did live commercials for a teen dance program. Later, though Frann didn't know a cumulus cloud from a cold front, she delivered the weather for a TV news show. Both gigs took place in St. Louis, where she was born and raised, the eldest child of Harry Luecke, a sports-writer for the Post-Dispatch, and Del, a housewife.

Close to her mother, who still lives in St. Louis, Frann speaks reverently of her father, who passed away last year. "I do miss him," she whispers. "His death is still real fresh to me." Because of Luecke's profession, Mary Frances (as she was known then), her two younger sisters and brother were immersed in athletics early on. "It was a great foundation for everything," says Frann. "You learn how to be a good sport. You learn how terrible it is to lose."

While attending a girls' Catholic high school, she shared a dream of acting with classmate Marsha Mason. "She and I were the ones who were always saying, 'We're actresses. We're going to make our marks someday,' " recalls Mary. "We were always huddling off to the side, making our plans about what we were going to do."

Just about this time, Mary began making a name for herself. Literally. She dropped the handle Luecke, chopped a syllable from her middle name and entered the national Junior Miss Pageant in her senior year. The only one among the battalions of earnest pianists, would-be opera singers and modern dancers to recite a humorous monologue, Frann was the hit of the Misses and went home with the crown and a college scholarship.

After two years at Northwestern, Mary got the job as weather girl. Her humorous meteorological musings quickly caught the attention of a producer at the ABC affiliate in Chicago, who offered Frann a job as correspondent on a local TV talk show. Frann enjoyed her Windy City job, which put her in front of actors like Marlon Brando, who, she says, made a pass at her in the middle of an interview. Eventually "I quit the show cold, because people started to think of me as a broadcaster," says Mary. "They were making inquiries about network jobs. And instead of being flattered, I said, 'Wait a minute. I'm an actress.' "

And so she was. She moved out to Los Angeles in 1969, where after a few months she was cast in a short-lived NBC series, My Friend Tony. Frann found her longest pre-Newhart job on the NBC soap Days of Our Lives, where she played troubled sophisticate Amanda Peters for four years. In 1982, after skimming along for a few years on TV guest shots, she was cast in Newhart. Although the show is now seven seasons old, Frann says, "I don't ever want to get too comfortable in my career or life. My nature is such that I'm always looking for new challenges."

She's also hoping to see some changes in her own life. Like a long-term relationship. Maybe a baby. "I would love to have a child," she says, sitting on the backyard patio of the sunny, flower-filled two-bedroom Benedict Canyon home she bought four years ago from Donna Mills. "I absolutely would." Frann has been single since 1983 and the end of her 10-year marriage to actor-turned-agent T.J. Escott. She calls the breakup "heart wrenching, incredibly difficult. If you have come to the decision that the two of you cannot live together anymore as man and wife, nobody escapes the pain. I will never believe a person who says to me, 'No problem leaving.' "

These days, says Frann, "I'm on my own, but I'm not alone. I see men." And while she claims not to seek any special requirements in said men, those who end up by her side tend to share a certain characteristic: They're young. Her current date, for example, is actor Bruce Deziel, who's 27. "I like a boyish quality in a man," says Frann, "somebody who is still adventurous. But I have no rules. I do not care—within reason—about your chronological age. I care whether you have passion in your life."

Tabloids have repeatedly linked her with another young man, talk show wunderkind Arsenio Hall. Frann pleads guilty only to minor involvement; the two went tandem to the People's Choice Awards last spring. "We're friends. I like him enormously," says Frann. "I've been in the tabloids a lot lately. You have to laugh about it. I do wonder why they say that Arsenio and I are getting married, when I've called them personally and told them the true story."

And what might that be? Says Frann: "That I'm pregnant with an alien's baby." Make a helluva TV movie.

—Joanne Kaufman, Michael Alexander in Los Angeles