Kendra Wilkinson, 29. Courtesy/Reuters

Former reality television star Kendra Wilkinson, 29, recently revealed she was 18 when she first had sex with Playboy magazine founder Hugh Hefner, 88. Hefner was 78 at the time.

"Hef asked me to be one of his girlfriends and live in the mansion and I was like, 'I don't even know what that means, but hell, yeah! I'm there!' I was living in this small-ass apartment. … I was praying for anything to get me out of there,” Wilkinson said during an appearance on U.K. television show “I’m a Celebrity, Get Me Out of Here!”

Wilkinson eventually became one of Hefner’s top three girlfriends, along with Holly Madison, 35, and Bridgette Marquardt, 41. The three starred in former E! television series “The Girls Next Door,” which ran from 2005 to 2010.

"I moved in and weeks went by and I didn't know that sex was involved," Wilkinson added. "Because I knew nothing about Playboy. I had just graduated high school."

Wilkinson said Hefner asked her if she “want[ed] to come upstairs,” and that all of his girlfriends understood what that meant. Though she eventually left the infamous Playboy mansion to pursue other career goals, the 29-year-old said that Hefner genuinely cared for all of his girlfriends. “Hef really looks at them like real relationships,” she said.

The San Diego-born television personality is currently married to Philadelphia Eagles wide receiver Hank Baskett, 32.