KHLOE KARDASHIAN has been secretly speak­ing with O.J. SIMPSON in prison, begging him to answer a question that’s tormented her: “Are you my real dad?”

The disgraced gridiron great has confided to pals he had an af­fair with Khloe’s mom Kris Jenner when she was married to his best buddy Robert Kardashian – and he says she got pregnant with Khloe, reveal sources.

The “Khloe & Lamar” star is so emotionally obsessed by the persistent rumors she’s O.J.’s daughter that she recently began phoning the imprisoned football player – and is trying to get him to agree to a jailhouse face-to-face.

Robert Kardashian was a key member of O.J.’s “Dream Team” of lawyers that got him off the hook for the 1994 murders of his ex-wife Nicole and Ron Goldman – and up until his death in 2003, he firmly believed he was not the biological father of Khloe, who looks like neither of her two fa­mous sisters, Kim and Kourtney.

Jan Ashley – Robert’s wife after Kris – revealed earlier this year he had expressed doubts that Khloe was his child.

“Khloe decided she can’t wait any longer, so she decided to reach out to O.J. at Lovelock Correction­al Center in Nevada and confront him with the pressing question: ‘Are you my real dad?’” revealed an insider.

“O.J. has told friends he is Khloe’s dad and he’s never denied it whenever his pals have asked.

“Khloe is telling friends she wants to look into O.J.’s eyes when she asks him if he’s her real father. Even if he denies it or just laughs it off, she believes she’ll be able to know the truth.

“Khloe has spoken to O.J. over the phone, expressed her feelings and asked that he meet with her.

“He got up the courage to talk to her because he knew it was important to Khloe, but he was noncommittal. He told her he would think about it and call her back. That was several weeks ago, and Khloe still hasn’t heard from him.”

The ex-football hero is stall­ing because he’s not sure how to handle the situation and has been retreating more and more from life outside prison, said the insider.

“Simpson explained to a friend, ‘The more I think about the out­side, the more painful it is to be in prison. I enjoyed talking with Khloe and asking about her family, but I froze up when she asked to see me.’ ”

Despite O.J.’s foot-dragging, Khloe is still pushing for a sit-down with Simpson, who went to prison in late 2008 for his role in an armed rob­bery of memorabilia in a Las Vegas hotel room. He won’t be eligible for parole until 2017.

But Khloe can’t wait that long for a show­down, the insider told The ENQUIRER.

“Khloe can’t let go of her sus­picions Robert Kardashian isn’t her real dad. She’s become com­pletely obsessed and is dying to know the truth.”

Although her mother Kris has told her O.J. is not her father, the 28-year-old reality star “still has her doubts,” disclosed the insid­er. “And she’s on a mission to get answers!”