Williams has made the revelation in her new book "You Have No Idea". She has explained how an 18-year-old woman molested her during a family trip with friends, reports tmz.com.
"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," Williams wrote in her book.
"I think I was highly sexualised because I was in fifth grade and I had this experience. 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," she said.
In her book, she also reveals she had an abortion during her high school years, but kept it a secret from everyone, including her mother, because she was scared.
But now the actress says she is is focused on moving forward. "I have learned to embrace my past. I embrace the choices that I have been given in my life," she said.