On "Oprah's Master Class," Vanessa Williams opened up about being molested.

Before she started the fifth grade, she went to California with a family friend for vacation. She had asked her parents to go as she had never been to California, and her family friend stayed at another friend's house, which is where the incident took place.

At that house, there was an older girl, who Williams described as "one of the cool girls." She had offered Williams cigarettes and made her want to feel more "grown-up."

Williams went on to describe the incident.

"One night she came into the room where my friend and I were sleeping," she said. "She told me to lie down on the floor, and she took my bottoms off ... and I knew I shouldn't be saying anything, and I didn't tell anyone."

As a 10-year-old girl, Williams didn't understand what was happening. Although she said it felt "good," she knew it "wasn't supposed to be happening."

When she returned to New York, she wanted to tell her parents. But when she saw her father, she knew something was wrong. His brother had just died, so she tried to suppress it.

"It awakens your sexuality at an age where it shouldn't be awakened," she added. "Had that not happened in my life and had I had an opportunity to have a normal courtship with a boyfriend at 16 or whatever ... there wouldn't have been that shame that was always haunting me. It made me more sexually promiscuous and more curious at a younger age than I should have been."

It's not the first time Williams has spoken about being sexually abused. Her 2012 book "You Have No Idea" was the first time she revealed she had been molested, notes ABC.