Happy Father's Day, O.J. Simpson -- the NOT father of Khloe Kardashian!

The former footballer-slash-murdered joined Twitter yesterday, on Father's Day, to spread a message and that message is ... Robert Kardashian was "like a brother" to him and "never in any way shape or form have I ever had interest in Kris -- romantic, sexually -- and I never got any indication that she had any interest in me."

Simpson said she's very "proud" of Khloe, just like he is of all his late friend's kids, but claims Khlo is "... not mine!" So there you have it! Straight from the horse's mouth -- O.J. Simpson says he's NOT Khloe Kardashian's father! Well, glad he put that rumor to rest!

Happy Father's Day, Juice!