How's this for a sitcom premise: A slightly daffy female TV personality with no journalism background is hired by a struggling news program to boost the ratings with her own brand of "happy talk"—much to the dismay of the presiding Rather-like anchorman. If that sounds vaguely familiar, it's because Mariette Hartley, 42, plays exactly that role with co-star Bill (The Incredible Hulk) Bixby on CBS' new Goodnight, Beantown and has played it once before in real life. A few years back Mariette filled in for Jane Pauley opposite Tom Brokaw on the Today show for three ill-starred weeks. The memory still makes her wince. "I came from Hollywood, and I felt I had entered Dressed to Kill," recalls Mariette, whose tendency to misidentify guests amused many reviewers but enraged the Today staff. "It really was almost like an enemy camp," she says.

Happily, the auguries are better for Beantown. Good ratings for the five-episode limited series point to its return next fall. And that should make Hartley even more familiar to viewers than she has become as James Garner's sassy sidekick in her famous Polaroid commercials. With Beantown, she has found in old friend Bixby an onscreen harmony similar to the one she developed with Garner. "I have even more rapport with Bill than with Jimmy," says Mariette. "Bill is quicker—he's like a terrier while Garner is more of a sheepdog." Bixby is equally enthusiastic. "She's one of the most honest people I've ever met," he says. "It's rare to find that adult chemistry in a business that's so childlike."

A protective mom who once had qualms about actively pursuing a career, Mariette took the role because her children, Sean, 6, and Justine, 4, now are old enough to accept their working mother's absence. "I have a hunch the kids are ready for this," says Hartley, whose husband, French-born producer-director Patrick Boyriven, 44, was associate producer of NBC's futurist drama V, scheduled to air this week. The children are frequent visitors to the Beantown set, and Hartley reserves 15 minutes of "special time" for each one (Mariette joins whatever activity the child suggests) every night. Lately she has also served on the board of the California Child Study Foundation and raises money to help hyperactive children.

Those interests surely stem from Mariette's own childhood. She was born in New York City to an advertising exec and a housewife, and her grandfather was pioneering behaviorist John B. Watson, who believed parents shouldn't touch children except for a light kiss when they were sleeping. "For many years during my adolescence, I didn't know where to put the need to touch," says Hartley, who by her early teens was precociously studying with famed actress Eva Le Gallienne. After high school Mariette spent a year studying drama at Carnegie Tech (now part of Carnegie-Mellon University) in Pittsburgh, before Le Gallienne introduced her to John (The Paper Chase) Houseman, then artistic director of the Stratford, Conn. American Shakespeare Festival. He gave her a job as an understudy in A Midsummer Night's Dream. She never returned to college, instead choosing theater.

At 19, she married a publicist and moved with him to L.A., making her screen debut in Sam Peckinpah's Ride the High Country. Then in quick order her marriage broke up, and a doctor's treatment of an illness misdiagnosed as hepatitis nearly killed her and cost her a promising contract with MGM. Discouraged, she moved to her parents' home in Brentwood, Calif., where, not long after, her father committed suicide. "When those things happened," she recalls, "it was like falling into a well. The vortex kept building until I was pulled out by therapy."

After three years of analysis she returned to Hollywood, where she found work on ABC's Peyton Place, in workshop theater and as a dress saleswoman. "I lived alone for 12 years, since I had to learn to like myself," Mariette says. "Then I met Patrick [at a 1975 test for an orange juice commercial in New York] and our two worlds came together. I wanted his children, and he wanted mine."

Mariette and family now live in the San Fernando Valley in a rambling house that they've been renovating for two years. With her revitalized career, Hartley's joy in her work, marriage and motherhood is at its peak. Her wit, spontaneous warmth and maturity are heightened by a resiliency gained through the passage of some difficult years. "When you reach 40, you may still have a fear of pain," she philosophizes, "but you also have the knowledge that you'll survive it."

Now Mariette has gone back into therapy to help her cope with success. "The one thing that's always scared me about success is being recognized," she says. "But it can also be funny. I hear the ladies in the next aisle in the supermarket saying, 'There's Mariette Hartley—boy, does she look like s—!' " It's that kind of winning self-deprecation that should keep Mariette recognized for years to come.