In a new interview with Rolling Stone, Kardashian recalls walking in on her stepfather, who was then known as Bruce Jenner, wearing women's clothes in the family garage. She reacted by running away, despite the fact that she had heard rumors about Caitlyn's cross-dressing habits for 10 years.
"I was shaking. I didn't know if I'd just found out his deepest, darkest secret, and he was going to come after me," Kardashian, who was 22 at the time, tells Rolling Stone.
Within the hour, Kardashian and Jenner had spoken on the phone and Jenner swore Kardashian to secrecy, promising, "One day, I'll talk to you about this."
Before coming out publicly as transgender earlier this year, Jenner talked to all of the Kardashian and Jenner children about it. The conversation with Kardashian happened in 2011. Kardashian continued to keep the secret in her family, only telling now-husband Kanye West - who she says was even more accepting than she was - shortly before they married in 2014. "I thought that Kanye should know that this is the reality about one of his daughter's grandparents," she tells Rolling Stone.
But the first time Kardashian truly met Caitlyn Jenner was at the photo shoot for her Vanity Fair cover. "She's beautiful, and I'm so proud that she can just be her authentic self," Kardashian says now. "I guess that's what life is about."