By Lisa Respers France
PHILADELPHIA (CNN) -- While Lady Gaga went public in 2014 with her story of being raped, apparently, not everyone in her family heard it.
The singer has revealed that her grandmother and aunt didn't know she was a survivor until her powerful Oscars performance Sunday night.
"My grandmother (in the middle) and my Aunt Sheri (on the right) both called me the day after the Oscars because I never told them I was a survivor," Gaga wrote in the caption of a family photo she posted on Instagram on Tuesday.
At the Academy Awards, the superstar performed "Til It Happens to You," the Oscar-nominated song she co-wrote with Diane Warren for "The Hunting Ground," a CNN documentary about rape and assault on college campuses. Vice President Joe Biden introduced Gaga's performance, and she was joined onstage by other survivors.
The emotional moment moved many in the audience.
Gaga further explained in her post that she was "too ashamed. Too afraid" to discuss with her family being raped at the age of 19 "because I'm Catholic and I knew it was evil but I thought it was my fault."
She told Howard Stern in 2004 that an older man took advantage of her and that she never confronted him.
"I thought it was my fault for ten years," she wrote in her Instagram post. "The morning after the Oscars when I talked to my grandmother Ronnie, with tears in her eyes I could hear them welling through the phone she said to me 'My darling granddaughter, I've never been more proud of you than I am today.' "
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