"I feel now might be the time to reveal a few of my most painful memories," the former Baywatch star told the audience. "At the risk of over-exposing myself, again, or being inappropriate, again, I thought I might share with you why I am doing this."
Anderson, 46, went on to reveal a long and harrowing history of childhood sexual abuse, which began at age 6 when she was molested by a female babysitter.
At age 12, she was raped by the 25-year-old brother of her friend's boyfriend.
"I went to a friend' boyfriend's house," she recalled. "The boyfriend's older brother decided he would teach me backgammon which led into a back massage which led into rape -- my first heterosexual experience."
When she was in ninth grade, Anderson said that her first boyfriend plotted to gang rape her.
"[He] decided it would be funny to gang rape me with 6 of his friends," she continued. "Needless to say I had a hard time trusting humans."
Anderson said her love of animals helped her heal from her traumatic childhood.
"My affinity with animals saved me," she said.
The event, which doubled as the launch of her foundation, also raised $150,000 for Cool Earth, which works to end deforestation.
"I want people to know - they can overcome and prosper with love," Anderson tweeted of her speech.