Actress Mischa Barton has said she has spoken publicly about attempts to sell a sex tape of her to prevent other women suffering the same "pain and humiliation".
Barton appeared at a news conference in Los Angeles after her lawyers obtained a court restraining order over the video and photographs. Police have also begun an investigation.
The British-born actress said: "I came forward to fight this not only for myself but for all the women out there.
"I want to protect them from the pain and humiliation that I have had to go through. No woman should have to go through this."
The images were recorded in the last year by someone she had a relationship with, but without Barton's consent.
It is claimed they have been offered for sale to the highest bidder.
She said: "My absolute worst fear was realised when I realised that someone I thought I loved and trusted was filming my most intimate and private moments without my consent, with hidden cameras.
"Then I learned something even worse: that someone is trying to sell these videos and make them public.
"It is a very hard thing to do but I am glad that I am finally standing up for myself."
Her lawyer Lisa Bloom told reporters that the images were a form of domestic abuse and the restraining order forbids the defendant from distributing, showing, giving or selling them.
She said anyone who passes the images along would be considered an agent of the person who took the images and would be covered under the restraining order.
"Revenge porn is a very common crime. It happens to a lot of people. It happens to people who are not celebrities," she said.
"It happens to the girls and women who are followers of Ms Barton. And it's scary, even for a celebrity, to stand up like this but it's important for girls and women to stand up for our rights."
Barton, who is a dual British-American citizen, achieved fame as a fashion model and actress in TV shows including The OC and movies including Notting Hill.