Is Khloe really a Kardashian? Fans have been asking that question for years, but now, a shocking new report has given the rumors their strangest twist yet: O.J. Simpson's manager, Norman Pardo, has come forward to claim that the notorious incarcerated former football star is her real father!

The truth, "is going to come out sooner or later," Pardo tells In Touch. And he believes that the real story is that Simpson and Khloe's mom, Kris Jenner, conceived the youngest Kardashian sister during a drunken hookup.

Kris, her husband Robert Kardashian, and O.J. and his then-wife Nicole Brown Simpson"all took their vacations together," Pardo explains. "There was a lot of partying going on back then. Kris cheated on Robert. She was known for having a good time."

But did that include a hookup with Simpson? Says Pardo, "Whenever I bring it up, he giggles."

Kris' own sister, Karen Houghton, confirms to the mag, "Yes, there are rumors that Kris and O.J. had an affair. And there are rumors that O.J. could be Khloe's father. I know O.J. was trying to contact Kris from jail."

And a report in last week's Star magazine claimed that her ex-boyfriend Cesar Sanudo also accused her of cheating with the football star.

Kris denies the claim, telling In Touch, "This is an absolute lie and not true. I have never had an affair with O.J. Simpson."

But Simpson's manager hints that he could be preparing to tell his side of the story with or without Jenner's consent. If a judge grants Simpson's request to be released pending a new trial in December, Pardo claims, Simpson plans to air more information about his relationship with the Kardashians.