A talking automobile certainly is nothing to strip one's gears about in a medium that already has witnessed twitching witches, favorite Martians and the likes of Mork from Ork. But NBC's Knight Rider, a sort of kindergarten crossbreed of My Mother the Car and Moonraker, may be the first TV show in which a one-and-a-half-ton steel-and-rubber prop has evinced more charisma than its flesh-and-blood star. Indeed, at the beginning of the action-escapist show, David Hasselhoff, 30, who plays the supercar's driver and resident Lone Ranger-in-Levi's, was pulling in less fan mail than his computerized, indestructible, crime-fighting Pontiac Trans Am (whose voice is provided by William Daniels, of NBC's St. Elsewhere). Since then Hasselhoff's role has been souped up a bit, and the stone-faced star now outdraws his metallic steed in letters by three to one. Moreover, Hasselhoff recently won the People's Choice Award for favorite male performer in a new television program (the Trans Am wasn't even in the running).

Still, Hasselhoff admits that playing second fiddle to a four-wheeler has its problems. "Once at L.A. airport," he recalls, "this woman ran up to me and hugged me and turned to her husband and said, 'I've been watching him on TV. Isn't he gorgeous?' The husband snarled, 'You're nothing without that car.' I got angry and asked him, 'Why don't you ask for the car's autograph?' I'm too sensitive—it's something I have got to get over."

David certainly never encountered such problems during his six years as heartthrob "Snapper" Foster on the CBS soap The Young and the Restless. When he resigned from the serial last year, he had "only" $30,000 in the bank and "didn't know where I was going, but I knew I had to leave." His worries were quickly alleviated by Brandon Tartikoff, president of NBC Entertainment, who invited him to try out for Knight Rider (Hasselhoff's first prime-time series, 1980's Semi-Tough, expired after four episodes).

The screen test was a near disaster. Hasselhoff climbed into the Pontiac Trans Am and "couldn't remember one line. I asked for five minutes to get it together, went backstage and shouted at myself, 'You are the Knight Rider!' I walked back in and did the scene dead on." He won the part. "I was so excited I literally screamed for joy," recalls Hasselhoff, who now rakes in more than $15,000 a week—compared to $5,400 during his soap opera days.

The new series also has paid off for Hasselhoff's live-in girlfriend, Catherine Hickland, 27, a 5'5" green-eyed blonde who played the young, romantic Courtney Marshall in the 1980-82 soap Texas. Hickland recently created the story line and starred in a Knight Rider episode called "White Bird," and she and David became engaged the day the episode wrapped. (She now sports a carat-and-a-half diamond engagement ring she calls "Gibraltar in a setting.")

Hasselhoff and Hickland met at the 1981 Daytime Emmy Awards in New York. "He begged me for a date and I said 'No,' " she laughs. "I'm generally not attracted to 6'4" men who look like Ken dolls," sasses Catherine. "They're too much trouble with their egos. He went back to L.A. and called me every other night screaming, 'I'm in love with you,' but I kept saying, 'No, no, no.' Then in September I came to L.A. on a business trip. We went out together and we've been together ever since." A member of a nondenominational church called the Hiding Place (Stevie Nicks of Fleetwood Mac recently married a church member), Catherine wears a small gold "Try God" pendant and carries her Bible everywhere. "I don't think David's too crazy about it," she says, though Hasselhoff, a lapsed Catholic, confides, "It doesn't faze me."

Born in Baltimore, son of a Brinks executive and a "housewife and stage mother," Hasselhoff started acting in school at age 7, had leading roles in high school productions, and worked dinner theaters in Chicago before arriving in L.A. in 1971. He broke into soap operas after a top agent, the late Joyce Selznick, discovered him in 1975 when he was a waiter. His new wealth has enabled Hasselhoff and Catherine to bid on a $450,000 four-bedroom home on Mulholland Drive, complete with requisite swimming pool and panoramic view of L.A. Until negotiations are complete, they'll share David's messy one-bedroom home in the Hollywood Hills with two cats and three parrots.

Off the Knight Rider set, Hasselhoff spends his time making personal appearances for NBC and Pontiac and visiting terminally ill and handicapped children. ("Because I am 'Michael Knight,' I can make kids smile," he explains.) He is also one of the founders and owners of the Ideas That Sell Toy Company, which so far has marketed 500,000 "rag balls" at $3.95 each. ("It acts like a hardball but doesn't hurt if it hits you.") Hasselhoff admits to being somewhat hurt by jokes about his show and his acting ability (the Washington Post called him a "zero" in one review), but he knows it's all part of the trade. "I think what Catherine likes best about me is my sense of humor," he says. "If you lose that in this town, you might as well not go on."