Khloe Kardashian -- I Had Sex With OJ Simpson -- Kidding?

Khloe Kardashian got juiced by OJ ... or so she says ... unless she was kidding.

Khloe guest hosted "Chelsea Lately" Wednesday when she dropped an apocryphal bombshell, telling the audience she "f*****" OJ Simpson.

It seemed like a joke, because she said it on the heels of grousing about false tabloid rumors. But then she said, "because I did f*** him once."

Khloe was 10 during the trial. She was 24 when OJ finally got a dose of justice and landed in prison for kidnapping.