By Sue Reilly
Updated October 16, 1978 12:00 PM

John Travolta and Olivia Newton-John sing the movie-stopping Summer Nights in Grease, but it was co-star Jeff Conaway and Rona Newton-John, Olivia’s older sis, who actually lived the movie’s paean to unexpected passion. Their courtship began not in a drive-in but at an Allan Carr party during the filming of Grease.

“I looked across the living room and saw this terrific-looking lady talking to Olivia,” remembers Conaway, 28. “I decided to go over and take charge before the pack of wolves descended.” Rona, 35, an aspiring singer-songwriter from England visiting her sister, noticed him too. “I’d go to the Grease dailies [rushes] with Livvy and kept asking, ‘Who’s that?’ whenever Jeff came on the screen,” recounts Rona. “She’d tease and say, ‘That’s the stud.’ She made him sound pretty dangerous. I almost fainted at the party when he turned out to be this polite, clean-cut boy. I liked him straightaway.”

One year later Conaway is riding high as Bobby Wheeler, the would-be actor in ABC’s hot new Taxi. Rona is writing songs and a film treatment. “I’ve never really gotten my career off the ground,” Rona says, but lately there’s been an excuse: She’s just finished decorating the suburban L.A. home they moved into together.

It was with trepidations, because they had toted up three failed marriages between them. Jeff’s, to an actress, didn’t last a year, and he reports, “I told Rona my relationships tend to go down the drain because of my seriousness about my work. She really understands.” Rona admits: “We have loud fights sometimes, but we’re not vicious. We really care about each other.”

For one thing, that means coping with their seven-year age difference. “Because of my woman’s vanity,” says Rona, “there are times when I get to feeling insecure, but Jeff doesn’t seem to have any qualms.” He says his buddy Travolta’s relationship with the late Diana Hyland, 18 years his senior, was instructive: “When you saw them together, the age thing was so inconsequential. They were a magic couple, and they grew into it. I think there’s a lot of Diana in Rona.”

Rona’s divorce from her second husband, an Australian-born musician, is pending, but Rona’s 4-year-old son, Emerson, and Conaway have already achieved detente. “Emerson loved having me all to himself and was very rude to Jeff,” says Rona. “One day he simply turned Emerson over his knee and spanked him. From that day they’ve been fast friends.”

Conaway and Newton-John both come from broken homes. Conaway’s parents, an actress and a New York ad man, split when he was 3. “I kept wondering why things weren’t more like The Donna Reed Show or Life with Father,” he recalls. But the childhood summers he spent with his South Carolina grandparents proved handy at 10 when he and his mother both auditioned for the stage adaptation of James Agee’s A Death in the Family. The director needed a boy with a Southern accent, and while his mother got a “We’ll call you,” Jeff’s career began with an 11-month stint alongside Colleen Dewhurst, Lillian Gish and Arthur Hill.

He quickly became a touring pro, though he says: “All I remember is the insides of buses, theaters and hotel rooms. There wasn’t much time for fun and games.” Later Conaway attended Quintano’s School for Young Professionals in New York, and at 15 he and four friends formed a rock group called 3½. It opened for acts like Chuck Berry and Gladys Knight and the Pips. When the group disbanded—over such squabbles as who would stand where—Jeff enrolled in North Carolina School of the Arts, later transferring to NYU (where he learned body movement from Martha Graham).

“I left three months before graduation,” he says. “There were hard feelings because I had the lead in a school production of The Threepenny Opera. But I was offered Grease on Broadway. Broadway! I couldn’t turn it down.” By the end of his two and a half years with the show, he took over the lead while some kid named Travolta was just another hood in the chorus. “When I would be singing, John would whisper with his back to the audience: ‘Jeez, Conaway, try to get on key.’ ” But Jeff adds, “We’d sit and talk later about making it big.” For Conaway, TV parts and movies (The Eagle Has Landed, Pete’s Dragon) came regularly before he landed the film part of Kenickie by “slicking my hair back, showing up for auditions with chains and a knife in my pocket and scaring the shit out of the poor guys reading with me.” His rented house in California burned the night before shooting began on the film, but so much for setbacks.

Success for Rona has proved harder. She grew up in Cambridge and later Australia, where her scholar father was a master at the University of Melbourne. When her sister was born, Rona was 5, and she remembers, “Olivia was always so pretty and my parents made over her so. When she got older I used to lock her in closets and was just generally mean to her.”

Rebellious (“I wore my skirts too short and my bleached hair too long”), she was bounced from school at 16 and dispatched to live with London relatives. After a year “running around and modeling for Vogue,” she returned to Melbourne and at 18 married a restaurateur 10 years older. “It was misery,” says Rona. They divorced after five years, and then she moved to England, where she married again in 1971. That match too became “shaky,” but old nemesis Olivia was supportive. “She knew I was having problems,” says Rona, “and we became best friends.” Rona cut demos for an American record producer, fruitlessly, and by June 1976 she had left her husband and moved into a tiny Beverly Hills apartment with British actress Jane Seymour. The next year Newton-John met Conaway.

“I feel we will marry someday and be happy,” figures Rona. For now the best sign is that both egos finally seem under control. “The other day Jeff was teasing me about being a prima donna,” says Rona. “Then he said seriously, ‘You know, in all our relationships we have always each been the star. With you, I’m willing to go for equal billing.’ ”