The mystery of who fathered Michael Jackson’s children may have been solved.

The Beverly Hills dermatologist who treated Jacko appeared to reveal a clue on Facebook. Arnold Klein updated his profile pic on Wednesday with an overlay of his drivers license photo and a picture of Jackson’s oldest son, Prince. On Facebook, Klein mysteriously posted, “Hmmmmm” without further comment.

The facial features are strikingly similar. The late "King of Pop" always maintained he was the daddy, and despite plenty of speculation, Doctor Klein denied any paternity rumors -- until now. Prince’s mother is Debbie Rowe, who just happened to be a medical assistant in Klein’s office. She earned a reported $6 million to carry Michael Jackson’s children. She's sworn to secrecy. All we know is that the parents -- whoever they are -- conceived not in the bedroom, but in a test tube.