She continued: "I went to her boyfriend's house. And his older brother decided to teach me backgammon, which led into a back massage, which led into rape - my first sexual experience. He was 25 years old and I was 12."
Anderson also said that a former boyfriend had arranged for her to be gang raped.
And she detailed her difficult home life, explaining that her father was an alcoholic, while her mother tried to hold down two jobs.
"My parents tried to keep me safe, but to me the world was not a safe place," she said.
Ms Anderson said she had found solace from her traumatic childhood in her love for animals, which were "my only real friends until I had children".
She said: "My loyalty was with the animal kingdom and I vowed to protect them and only them."
The Pamela Anderson Foundation is dedicated to human, animal and environmental rights.
According to its official website, the charity aims to challenge communities and worldwide politics in a "provocative way".
Ms Anderson's husband Rick Saloman was in attendance at the event, as well as fashion designer Dame Vivienne Westwood.
More than US$150,000 (NZ$174,000) was raised for Ms Westwood's chosen charity Cool Earth.
- Independent
