Viola Davis said Sunday that her own experiences with sexual assault led her to become an advocate for the Rape Foundation and encouraged others to visit treatment centers so they'll become supporters. "You must,'' she said. "And then let your heart do the rest.'' "Myself, my mother, my sisters, my friend Rebecca, my friend from childhood, we all have one thing in common: We are all survivors of sexual assault in some way, shape or form,'' Davis said Sunday at a benefit for the foundation. It provides free medical treatment, counseling and legal aid to sexual assault victims at its Rape Treatment Center and Stuart House, which specializes in caring for sexually abused children. An advocate for the group since playing its founder in a 2010 film, Davis was among the guests of honor at the organization's annual fundraising brunch held at billionaire Ron Burkle's Greenacres estate in Beverly Hills, California. Davis said half of the survivors helped by the Rape Foundation are children, adding that one in four girls and one in six boys are sexually abused before age 18. Her own sister is among the casualties: She was sexually assaulted at age 8 and still struggles today. "I continue to pray for my sister,'' said Davis, who has previously spoken publicly about her sister's attack. The brunch was held in a tented space in Burkle's backyard, where "Black Panther'' star Chadwick Boseman, "Vampire Diaries'' actress Nina Dobrev and the supporting cast on Davis' "How to Get Away With Murder'' were among the guests in 95-degree heat. David Schwimmer was the master of ceremonies. The actor-director started working with the Rape Foundation during his "Friends'' days and has served on its board of directors for the last 12 years. He said the brunch supports a year's worth of services at the Rape Treatment Center and Stuart House. The Rape Foundation also provides educational programs for first responders and middle- and high-school students.