Khloe Kardashian has always seemed a bit different from her sisters Kourtney and Kim. And maybe now we know why.

Jan Ashley, the late Robert Kardashian's ex-wife, told Star magazine that while Kris Jenner is definitely her mom, Robert was not Khloe's father.

"Khloe is not his kid," she says. "He told me that after we got married. He just kind of looked at me and said [it] like it was a matter of fact. He said, 'Well you know that Khloe's not really a Kardashian, don't you?' And I said...'OK,' and that was it."

Ellen Kardashian, whom Robert married six weeks prior to dying in 2003, says this is the case as well.

"Khloe brought it up all the time," she says. "She looked nothing like the rest. She was tall, had a different shape, light hair, curly hair. Didn't look anything like the other three children. [But] he never would have considered a DNA test. He loved her very much."

So who's the daddy?

[OK!]