A Star is Born

Beautiful Cynda Williams, who plays Clarke Bettancourte in Spike Lee's jazzy new romance Mo' Better Blues, had to bend over backward to get a break in Hollywood. Literally. The 24-year-old actress was introduced to moviemaking by being tethered to the railing of a Manhattan apartment terrace 39 stories up and asked to enact a wildly imaginative love scene with actor Wesley Snipes, who plays a saxophonist named Shadow. ''That was the very first shot of my life,'' says Williams. ''I thought, 'If I can do this,,I can do anything.'''

Judging from early reactions to Blues, an $11 million production with a sharp ensemble cast led by Academy Award-winner Denzel Washington (Glory), audiences and critics are apt to agree. Williams slipped into her role as Clarke, a stunning, self-assured jazz singer looking for a career break, as comfortably as she dons her slinky red dress in the film. A classically (trained singer who has been performing since childhood, she seems miraculously free of self-doubt. Wasn't she at all innimidated about working with the likes of Denzel and Spike? ''If they have enough faith in me to give me the role,'' she says, sipping cranberry juice in a Manhattan restaurant, ''then I have enough faith in myself that I can do it. I'm not afraid of success. I welcome it.''

Williams' parents, Charles, a Chicago policeman, and Beverly, a medical lab technician who lives in Muncie, Ind. (they are separated), may have found their daughter's nude love scenes in Bluesa bit disconcerting (''Well,'' says Beverly bravely, ''she has a beautiful body''), but they are delighted about the fact that she is carrying on a family musical tradition. Cynda's grandfather, R.J. Williams, a well-respected Methodist minister in Muncie, let Cynda sing in his church choir as a youngster. Her parents also dabbled in singing, and an uncle, James Williams, was a professional musician who lived with the family and often brought his bands home to practice. ''I'd go down to the basement and listen to them play,'' says Williams. ''That's whereethe seed was planted.'' When James began writing musicals, Williams starred in them at community theaters in Muncie.