BEVERLY HILLS, Calif. — Jane Fonda told an audience of activists and philanthropists that her mother had been sexually abused as a child before eventually committing suicide at 42.

Fonda shared the personal story at an event celebrating the 40th anniversary of the Rape Treatment Center, which provides comprehensive free treatment for sexual assault victims. She hosted the Rape Foundation’s annual fundraising brunch Sunday at billionaire Ron Burkle’s Greenacres estate in Beverly Hills.

Fonda said that while writing her memoirs, she reviewed her mother’s medical records and discovered she had been sexually abused when she was 8 years old. Frances Ford Seymour committed suicide when Fonda was 12.

“The minute that I read that, everything fell into place,” Fonda said from a small stage set up in Burkle’s sprawling backyard. “I knew why the promiscuity, the endless plastic surgery, the guilt, the inability to love or be intimate, and I was able to forgive her and forgive myself.”

She said sexual violence is “epidemic,” vowing, “I will support the Rape Treatment Center for the rest of my life.”

Lily Tomlin introduced Fonda, her “9 to 5” co-star and longtime friend. David Schwimmer and Eric McCormack also spoke during the luncheon, where guests included Viola Davis, Emmy Rossum and Sam Waterson.

Gail Abarbanel, founder of the Rape Treatment Center and president of the Rape Foundation, introduced several rape survivors, including the mother of the victim of the 2012 Steubenville High School assault in Ohio. She noted her daughter’s bravery in pressing charges against her attackers — beloved star football players who had the support of the community.