DROOLED OVER BY JIM CARREY IN THE NITWIT HIT DUMB AND Dumber, she captivated her costar long after the cameras departed, and now the two are Snug and Snugger. "Jim is really handsome," says Lauren Holly, 31, of her on-again, off-again, elastic-faced beau. "People don't realize that because he's always mugging." Nobody, on the other hand, would overlook Holly's wholesome allure. The daughter of Up-state New York college professors, she was "the classic all-American girl," says her mom, Michael. As a high school cheerleader, however, Holly battled a weight problem—she was too skinny. Now 5'8" and 118 lbs., she remembers "drinking milk shakes every day" to fill out, yet "all that got me was a big butt." Now, as Maxine Stewart on CBS's Picket Fences, she's "the most beautiful police officer you'll ever meet," says the show's co-executive producer Michael Pressman. "I see her at 6 in the morning and 7 at night, and she always looks great." Whatever her secret is, you can bet it's not her persistent sweet tooth or perfunctory nightly workout in her Los Angeles home. Not a natural redhead ("I'm the only woman in Hollywood with blonde roots"), she'd love to fill the oversize shoes of fellow fake carrottop Lucille Ball. "She was beautiful," I says Holly, "and she had great legs." Sound like anyone we know?