By Jeannie Park
December 24, 1990 12:00 PM

At last, the Case of the Missing Aussie Singer is about to be solved. Tracked to her three-acre spread in the Malibu hills, Olivia Newton-John plops onto a chintz sofa and prepares to unravel the mystery of her recent whereabouts. In the ’70s and early ’80s she was a multimedia phenomenon—sort of a kinder, gentler Madonna—jamming the radio waves with Top 10 tunes (Have You Never Been Mellow, Summer Nights), swaying across movie screens in the blockbuster Grease, getting Physical on TV in her increasingly provocative videos. But then, poof, she disappeared from Hollywood. So where has she been? “It sounds kind of boring to say I’ve been at home,” she says. “But that’s the truth.”

Hard to imagine Madonna ever making that claim. Not that Newton-John, 42, has been lolling about, stuffing herself with bonbons (the schoolgirl-thin body in sweatshirt and black tights attests to that). By 10 one morning, she has already whizzed through a rather unmellow flurry of tasks: preparing an oatmeal breakfast for her husband, actor Matt Lattanzi, 31, and daughter Chloe, who turns 5 next month; caring for a whining puppy; welcoming mom Irene for a visit from Melbourne, directing a crew of cabinetmakers to the playroom and reviewing her lengthy list of afternoon appointments. Observing her daughter in action, Irene says, “It wears me out just watching.”

While managing this household hustle, Olivia has finally found time to pencil in one of her activities from the old days. In the NBC holiday trifle A Mom for Christmas, airing Monday. Dec. 17, she plays a mannequin who comes to life to care for a motherless girl. It’s her first dramatic venture since 1983’s Two of a Kind, the comic-romantic slip she made with fellow Greaser John Travolta. After that flop, Newton-John, who has always been nervous about performing, “toyed with retiring” and turned the volume of her career way down. But last September, when she sang four numbers in a benefit concert for California’s Big Green initiative, a pet cause, she found herself thrilled to be singing for a crowd. A week later she read the Mom script. “The timing was perfect.” she says. “I was full of confidence.” And more important, perhaps, “It was a story I could see Chloe watching and enjoying.”

It is Chloe, in fact, who calls the tune in Mom’s life these days. While Newton-John’s four Grammys are tucked away on a high shelf, Chloe’s artwork is framed and prominently displayed in the house. Concern for Chloe also sparked Newton-John’s ardent environmentalism. A goodwill ambassador for the United Nations Environment Program, Olivia practices what she preaches. Her front walkway is lined with recycling bins, and the family throws all their food scraps on a compost heap.

Despite her obvious talent for mothering (“She always told me to eat my greens,” says Juliet Sorcey, 11, her Mom co-star), Newton-John delayed starting a family, in part because of painful memories of her parents’ divorce. Her father, a retired college dean now living in Sydney, and mother, a corporate publicist, split when Olivia was 10. But after several years of living with Lattanzi—the only positive fallout from her 1980 bomb, Xanadu—she took the plunge and married him in 1984. Thirteen months later Chloe was born, and Newton-John put her already streamlined career on hold. “I wanted her to have a mother and not be raised by nannies,” says Olivia. “I had play groups at my house.”

Laughing, she recalls, “My agent constantly asked, ‘What do you want to do?’ My answer was always the same—nothing.” Lattanzi, who is still struggling to make an acting name for himself, says, “Olivia had a big career. I think that’s why she has been able to devote herself so fully to Chloe.” The couple agree on most child-raising matters. “Our biggest difference,” says Lattanzi, “is that I tend to be more of a disciplinarian than Livvy.” Their 11-year age split, which initially put Olivia off, seems not to be an issue.

Despite Olivia’s commitment to her daughter (she has had no hired child-care help), there has been time for a few business projects. Last year she recorded the Chloe-inspired Warm and Tender, and she has taped video prologues to a set of animated fairy tales (see page 27). She also keeps her hand in Koala Blue, the worldwide chain of sportswear boutiques she founded with her friend and fellow Australian singer Pat Farrar in 1983. “She’s extremely involved,” says Farrar. “She helps design, she visits stores, she helps with the catalog, all that.”

Her largest personal project is the construction of a 10,000-square-foot Malibu beach house, which Lattanzi is supervising. When asked whether they plan to expand their family as well, Newton-John recoils with understandable reluctance. Two years ago she suffered a miscarriage. “It was devastating,” she says. “I can handle it now, but it took a lot of time. My family and my husband helped me immensely. But I was lucky. I had a beautiful child, and if I never have another child, I’m blessed already. I can’t complain.”

Golden-haired like her mother, Chloe has only a vague idea of Newton-John’s previous life in the limelight. ” ‘She gets a kick out of hearing me sing, but it’s nothing special to her,” says Olivia. “Sometimes she’ll tease me by calling me Olivia Newton-John, and then laughing.”

Most of the time, of course, Chloe just calls her Mommy. “All I need to hear is ‘Good night, Mommy, I love you,’ ” says Newton-John, “and there’s no question everything is worth it.”

—Jeannie Park, Todd Gold in Los Angeles