Khloé Kardashian has long faced rumors that Rob Kardashian, Sr. is not her father — and her biological dad is actually former Kardashian family friend O.J. Simpson.

In a new book, Kardashian Dynasty: The Controversial Rise of America’s Royal Family, author Ian Halperin dives into the paternity scandal and what he would like to hear the former football player confess after all this time.

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"I crafted a letter that I hoped would pique the Juice's interest. My goal was simply to get a face-to-face meeting with the wife-killing maniac. If I could establish his trust, my goal would be to have him at least admit that he had an affair with [Khloé's mother] Kris Jenner back in the day,” he writes in an excerpt exclusively obtained by In Touch.

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"When I heard the rumors, I immediately dismissed them out of hand. While it's true that Khloé looked nothing like her sisters, I thought she was too light-skinned to have been fathered by O.J. — not withstanding the fact that he is a light-skinned African American with significant white blood in his ancestry. Still, [Khloé’s sisters] Kourtney and Kim [Kardashian] were darker than she was. They'd be more likely candidates, I assumed.”

kris jenner oj simpson splash

Kris Jenner and O.J. Simpson.

Ian adds, “Then I saw a photo of O.J.'s daughter Sydney when she was young and a photo of Khloé at a similar age. They were spitting images of each other. Maybe there's something to this after all, I thought."

O.J. never wound up responding to the letter.

Kardashian Dynasty: The Controversial Rise of America’s Royal Family will be available for purchase on April 19.