Vanessa Williams says she was sexually molested as a child by female teenager Carlo Allegri / REUTERS With her hilarious turns in shows like "Ugly Betty" and "Desperate Housewives," Vanessa Williams has built an acclaimed TV career on impeccable comedic timing and loads of laughs. But the actress has now come forward with news that puts a sobering spin on her life. Williams reveals that she was molested as a 10-year-old, which she chronicles in her new memoir, "You Don't Know." MORE: Mistrial declared in Nicollette Sheridan case In the book, which is excerpted in the latest issue of People, the actress recalls the details of the incident and reflects on the impact it's had on her life. According to Williams, she was visiting family friends in California when one night the family's 18-year-old daughter came into her room. "[She] pulled down the bloomers of my cotton baby-doll pajamas," Williams writes. 'What are you doing?' I asked. 'Don't worry--it'll feel good.' I lay there paralyzed. What was going on? I didn't speak. She kept at [the molestation] for I don't know how long. She slid my bloomers back up and whispered: 'Don't tell anyone.'  The actress kept the incident a secret for years but says its full impact only hit her when she was in college. MORE: Eva Longoria on Desperate Housewives trial--"It's a stain on our legacy as a hit show" "After that trip I felt something change in me," she writes. I had always been defiant, but I became a bit more rebellious. I began to pull away from my parents. The star also discusses the nude-photo scandal that led her to being dethroned as Miss America in 1984. But, she says, she's always remained open and honest--including to her children--about all the challenges she's faced. "When my kids have asked about Miss America, those photos or any other part of my life, I told them what I always tell them--the truth," she explains. After all, it was part of my journey that led me to them and to where I am today. PHOTOS: Desperate Housewives' OMG Moments!