It was some first date for a top model and a young millionaire. On a 35° November evening he took her by motorcycle to a noisy Manhattan restaurant and tried to persuade her to take up skydiving. That night four months ago resulted in three things: a runny nose, laryngitis and a new beau. Cover girl Christie Brinkley, 27, and champagne heir Olivier Chandon, 26, have been together ever since. "I like her smile and her sexy body, though that's not enough to stay with somebody," he says. "Her simplicity is very important to me." To which she pipes up: "He doesn't mean simpleminded."

With seven years in modeling and more than 150 magazine covers behind her, Brinkley still looks like a freshly minted California kid. It's hard to imagine that she once grubbed along for a period as an art student in Paris, or that she was married for eight years to a French political cartoonist named Jean Francois Allaux, or that she's unabashedly intrigued by continentals. "Now and then you come across one who's not inhibited," she says, "and then the European man really has something extra." However long the Brinkley-Chandon mutual fascination endures, "We're a fun couple," as Olivier puts it.

So they are. Christie makes some $350,000 a year posing for clients like Chanel No. 19, Cover Girl cosmetics and Anheuser-Busch's Natural Light beer. Although Chandon's ancestors founded Moët & Chandon, the leading sellers of champagne, Olivier struck out on his own. He came to New York two and a half years ago to work in sales at United Technologies (jet engines, helicopters, elevators), while studying marketing at New York University. He skis and sails; so does she. He's even talked her into skydiving. Christie loves boxing ("What could be more different from modeling?") and drags Olivier to fights. He also races cars, and will be driving in the North American Formula Atlantic Championships in Long Beach in April. Christie is less enthusiastic about this side of Olivier's sportif personality.

"I would prefer that he had a nice safe hobby," she shrugs, "but I try to support him at what he does." In Manhattan, she says indulgently, "In one evening he thinks he can do five different things. A half hour before the ballet starts, he says, 'C'mon, time to do tae kwon do [a Korean martial art].' Then we go to the ballet and sometimes leave at intermission to meet friends for dinner. You have to be in special physical condition to be a girlfriend of Olivier's."

They met at a Studio 54 party promoting the 1982 Christie Brinkley Calendar. Chandon went specifically to see her. "When I want to meet someone, nothing stops me," he says. Steve Rubell, the disco's former owner, made the introduction. Recalls Christie, "It was noisy, and I could only hear half of what Olivier said, but he was just so enthusiastic." Later he sent her a dozen white roses with a note saying he hoped to see her before the flowers died. She called him. "It was love at first sight," she says. "It's very hard to meet people. I've said no a lot. It was nice to be able to say yes."

Christie's dad is TV producer Don Brinkley (Trapper John, M.D.). Her mother, Marge, proudly recalls that "At 2½, Christie had a little woman's body. People always admired her." Perhaps prophetically, the gregarious Brinkleys have had a case or two of Moët & Chandon delivered every week for years. ("Christie and her mother," says a friend, "drink more champagne than any two people alive.")

As a teen, Christie was upset by the drug-taking at her high school and transferred to the Lycée Français in Los Angeles. She studied art at the University of California in both Los Angeles and Northridge, cutting out to Paris just before her senior finals in 1973 because of "a bad love affair." In Paris an American photographer encouraged her to try modeling. SPORTS ILLUSTRATED Associate Editor Jule Campbell found her in a California agency and launched her in the magazine's 1976 swimsuit issue. "She has great flair," says Campbell. "She can put a dress on backwards and make it look fantastic."

Olivier's father, Frédéric, runs Moët-Hennessy, as the company is called, from an office in Paris, hunts at a country estate and collects cars; his mother, Francesca Sanjust di Teulada, is a painter. Olivier went to the exclusive Le Rosey school in Switzerland and served in the French Air Force. He learned auto racing from his father and drove his first race at 18. But he says he hasn't been pushed to join the family business (and vows that his baby bottles were never spiked with champagne, as his dad's were). He drinks only juice, iced tea and "an occasional sip of champagne" and denies he's a playboy, though he was snapped with several international beauties (including Nastassia Kinski) before Christie. "A playboy doesn't really love women," Olivier explains. "He wants to keep score."

"I don't rate myself among the world's great beauties," she says, "and modeling is a 9-to-5 business with me. I don't take it seriously, but I am very professional." She has started acting and dancing lessons, but is wary of being "another model-turned-actress flop." Her real satisfaction, she says, comes from her own photography and painting. A non-cook, she is grateful that he can whip up some pasta and a salad. They live in her West 67th Street co-op, a 1,000-square-foot room furnished with only a dining table, a Japanese sleeping mat, a double hammock, her Guerciotti bike and books. (Her latest enthusiasms are authors Tom Robbins and Jerzy Kosinski.)

They don't talk marriage. "We don't even think about it," says Olivier. "I don't feel like signing a contract with someone I love." Christie believes "the only reason" to wed is to have kids. That gives Olivier pause. Says he, "I'd love to have children, but it's like they say in racing. One child makes you one second slower, the second child two seconds slower."

Can it last? "If Christie were ugly tomorrow," he says, "I don't know how I'd feel. It's difficult to pinpoint." And if Olivier were to wake up poor? "I'm in love with him, not his money," says Christie. What's important, she says, "is doing what you want to do."

In four months there have been few crises in their giddy lives, but they both know the importance of being flexible. For instance, there was New Year's Eve in Klosters, when after a full day of skiing they got dressed up for a party, then decided to stay home in front of a roaring fire. Just before midnight she went to the refrigerator and discovered there wasn't a drop in the house. Alors, the model and the millionaire toasted the new year with Earl Grey tea.