Witherspoon told the audience at the Elle Women in Hollywood Awards on Monday night that the recent revelation of decades of sexual misconduct allegations against producer Harvey Weinstein has prompted her own experiences to come back "very vividly".
Witherspoon said she had "true disgust at the director who assaulted me when I was 16-years-old and anger at the agents and the producers who made me feel that silence was a condition of my employment".
Witherspoon didn't name the director. Her publicist didn't immediately respond to a request on Tuesday for further comment.
Lawrence detailed what she called a "degrading and humiliating" experience of being asked early on in her career to lose 15 pounds in two weeks for a role. She was then forced to pose nude alongside thinner women for photos that she says a female producer told her would serve as inspiration for her diet, she said.
When she tried to speak up about the demands, Lawrence said she couldn't find a sympathetic ear from those in power.
"I was trapped and I can see that now," Lawrence added. "I didn't want to be a whistle-blower. I didn't want these embarrassing stories talked about in a magazine. I just wanted a career."
Lawrence said it wasn't until she was an A-list star that she had the power to say no.
Witherspoon expressed similar regret for not being more vocal about her experience, saying she has felt anxiety about being honest and guilt for not speaking out earlier or taking action.
For her part, Lawrence pledged to be an advocate for "anyone who has ever felt threatened in this industry".
