The official line on why Ashley Judd and race-car driver Dario Franchitti kept the news under wraps for five months is that they wanted to enjoy their engagement out of the spotlight. But L.A. jeweler Martin Katz knows better. It took Katz nearly four months (and several European trips) to nab the antique cushion-cut diamond—a stone shaped like a square pillow—for the center of Judd's engagement ring. After rejecting six jewels that he placed before her, Judd, 32, began to show her frustration. Says Katz: "It was time to let the world know, and she wanted a ring on her finger."

Four days before the April 29 announcement (which did not include a wedding date), Katz came through, presenting Judd with the diamond—of "substantial" carat, he says—in a unique platinum setting covered in 100 of the tiniest diamonds. For the onetime country Cinderella (Judd family lore has her cleaning out mom Naomi and sister Wynonna's tour bus for $10 an hour as a teen), the event has capped eight months of fairy-tale success that started with last fall's $116 million surprise hit Double Jeopardy. Now commanding $8 million a film, Judd has found her Prince Charming in Franchitti, 26, the son of George Franchitti—a Scot of Italian descent and father of three who sold his ice-cream-making business in Whitburn, southwest of Edinburgh, in 1997 to follow his oldest son's career—and his wife, Marina. When the couple met at a friend's wedding reception a year ago, Franchitti was already a star on the Championship Auto Racing Teams Indy car circuit (he placed second last year). Says Susan Cartsonis, producer of Judd's current film Where the Heart Is: "He's a calm, quiet, sweet guy with a nice sense of humor." And the good sense to flatter his future mother-in-law. "I just know Dario as the guy around my house who likes my tuna casserole," Naomi, 54, told PEOPLE last month. Adds Ashley's maternal grandmother, Polly Rideout, 72: "He adapts well to her lifestyle and she to his." Their courtship may have unfolded alongside the speedways of America (Judd has not only become a pit-stop fixture but taken up racing herself, coming in second to last in a recent celebrity race) and the runways of Paris (where the pair took in Valentino's show in January), but it's at home that Judd and Franchitti do most of their doting. When a stalker invaded Judd's 180-year-old Franklin, Tenn., house in September, Franchitti tailed him in a car until the police caught up. And when he suffered a cracked pelvis and concussion in a February racing accident, Judd nursed him back to health at her place. "They offer each other a sense of stability and security that they haven't found anywhere else," says Judd's close friend, makeup artist Ashlee Petersen. "The two of them figured, 'This is something special. Why wait?' "