Cosmopolitan, August 1992, Volume 213 Issue 2, p88, 1p, 1c By Maitland McDonagh She thinks "sexy" equals a big old shirt and socks....Her Significant Other right now is her Yorkie....Who is this wild Irish-American rose? One thing you can say for Moira Kelly: She doesn't hold out for glamour roles.  Adolescent manic-depressive (The Boy Who Cried Bitch), teenage murderess (Love, Lies, and Murder) impoverished orphan (Billy Bathgate)....she's played them all.  "I'm not aiming to be a movie start," she insists.  Nevertheless, starring roles keep coming her way, starting with the sleeper hit The Cutting Edge and continuing with David Lynch's Twin Peaks: Fire Walk With Me and Sir Richard Attenborough's Charlie, in which she plays Oona O'Neill to Robert Downey Jr's Chaplin.  She also be seen opposite Cuba Gooding Jr. in HBO's Daybreak a love story set in a plague-ridden America of the future. So what's the secret of her budding stardom?  "I've been lucky" she says nibbling on a slice of rhubarb pie in a bustling Manhattan cafe.  "I've never expected my career to take off this way.  I thought I'd be pounding the pavement just like everybody else, waiting to tables instead of being interviewed at one.  It's been hard, watching friends miss out on the roles and opportunities I've had -- they're just as talented." Raised on Long Island, the third of six children.  Kelly gravitated to performing early on.  She studied violin, sang, and gradually shifted her focus on acting, honing her skills by  playing elaborate practical jokes. "A friend and I once pretended to be English newlyweds looking for a house, and these three old lady realtors loved us for our 'darling accents.'  They questioned us for an our and a half about every detail of our lives, while we just rattled off complete fantasy answers.  We left feeling we'd done our deed for the day -- and knowing exactly how to by a house!" The Irish step dancing she studied as a child helped Kelly master ice-skating for The Cutting Edge although "by the end, I was bruised, bumped, torn, and tired."  That experience paled next to aging more then two decades as Oona O'Neill Chaplin, however, "If you want to be miserable," she says wryly, "just dye your hair gray for two months." Daybreak posed a new challenge: nudity. "My mom is settling into the idea, but I made her promise not to watch it," she confesses. Off screen, Kelly obviously has a laid-back approach to sexuality -- today she's wearing jeans and a T-shirt: her dark hair is casually pulled back in a ponytail.  "I dress down a lot, so anything that has to do with hells or skirts or panty hose seems hot to me," she says, taking another small bite of the pie.  "But to tell you the truth, I feel sexiest in a big old shirt and a pair of socks." No great television watcher - she'd rather read, draw, hike, climb, or ride -- Kelly went into the Twin Peaks movie without knowing much about the cult series.  Her role in it should please her mom -- "Donna's the goody-two-shoes girl on the block" --but found a kindred spirit in the notoriously bizarre director.  "David doesn't seem strange to me," she says.  "Maybe that's because I'm a little weird myself." And what about kindred spirits of the boyfriend kind?  "I haven't been settled in one place long enough to establish a relationship," she answers thoughtfully.  "I've been on the road for the last year and a half, and I don't like to mix business with pleasure.  But I do want to get married and have a big family.  I want to work with kids too.  I don't know how yet, but I think it will have something to do with theater." Does she have any sense of the sort of man who will complete this picture?  "My mother always says Mr. Right is the last person you'd expect him to be, so it doesn't make sense to sit around dreaming.  But believe me, the second he walks through the door, I'll grab him." For now, her constant companion is Cas ("for casual"), a miniature Yorkshire terrier who came to lunch nestled under Kelly's coat and is not napping contentedly on a chair. In any case, for the moment, this amazingly levelheaded twenty-four-year-old is focusing on her career.  "You have to take control," she says firmly.  "If you just site back, you'll end up doing the same stuff over and over, and you'll have only yourself to blame."  Then she throws back her head and laughs.  From his chair, Cas opens one eye, then yawns and settles down again. "There was this one script, called The Red Sneakers, that didn't get the, go-ahead," says Kelly.  "It was about a one-legged lesbian comedian.  And I said, 'I'm your girl--that's the role for me.'  To have pulled that off would've been really something!" HOBBY: People watching.  "It's fun to make up stories about who people are and where they're going." FAVORITE TEAMS: The New York Mets and Islanders, Detroit Lions, and Pittsburgh Steelers.  "I love going to games." MOST ADMIRED QUALITIES: "Loyalty--it's greatly underrated--and passion." PERFECT DATE ACTIVITY: "Hiking, because any man who can appreciate being close to nature is okay in my eyes."