April 17, 2012 -- When Vanessa Williams says "You Have No Idea," she means it.
That's the title of Williams' new, remarkably candid memoir, penned with her mother and available in stores now.
In the book, the "Desperate Housewives" actress reveals shocking secrets about her earlier years. The darkest one is that she was molested by an 18-year-old girl when she was just 10 years old, while they were on a family trip with friends.
"It was definitely a choice, because it didn't need to be [in the book]," Williams said of the incident. "It happened one night where she told me, 'come over here,'… I didn't know that it was wrong, but I knew that it wasn't right because I wasn't supposed to tell anybody."
The 49-year-old actress said that at the time of the incident, it was difficult for her to understand what had happened and she kept it a secret for years. It was not until many years later, when she was in college, that she even realized the significance of what had happened to her.
"I think I was highly sexualized because I was in fifth grade and I had this experience," Williams told "Nightline." "Because it feels good, you're like, OK, well this is supposed to be normal. That's not normal for a 10-year-old to be seduced."
Williams said she didn't even tell her mother about it until they wrote the book together. Helen Williams said she was "absolutely stunned" to find out.
"[I] had no idea that, that had happened," Helen Williams told "Nightline." "But in retrospect, it kind of put into place some of her reactions during her pre-teen years."
Vanessa Williams, now a mother of four, said she first got pregnant when she was in high school but decided to have an abortion -- another secret she kept from her mother.
"Being pregnant is the most frightening thing that happens in your life," she said. "I knew in high school that's something that I was not prepared to do, or fight, or struggle with."
In college, Williams got into beauty pageants and became the first black woman to ever win the title of Miss America in 1983. But the racist backlash she received over her victory was so intense, Williams said, that at times sharpshooters were stationed on buildings she was visiting in order to protect her. She said she also received numerous death threats.
"[My mother] wouldn't discuss them with me, because she didn't want me to be freaked out by them the entire year while I was doing my appearances," Williams said.
But Williams also had a wild streak that may have led to a public fall from grace. At age 19, she agreed to let a photographer take nude photos of her after he promised not to distribute them.
"I started out on top of a cab and ended up in a studded collar upstairs an hour later," Williams said. "That was my joke, saying, you know, 'How could I go from this trusting, you know, photo shoot, to being in S&M clothing within the same shoot with a guy I didn't know.'"
The photos ended up in Penthouse magazine – leading to a scandal that ultimately led Williams to give up her crown.
"I've learned to embrace my past," Williams said. "I embrace the choices that I have been given in my life."