(Photo: Facebook/Arnold Klein)Arnold Klein and Prince Michael Jackson.

Arnold Klein's Facebook post has sparked huge speculation that he could be the biological father of Michael Jackson's son, Prince Michael.

Klein used to be the dermatologist to the late King of Pop, and he recently sparked interest when he posted a photo onto his social media page contrasting an old photo of himself with an image of Prince Michael.

The posting, although cryptic, has caused many to suggest that he is hinting he is the biological son of Jackson's son.

The photo shows Prince Michael at the top with an ID picture of himself in front at the bottom of the photo. The photo was accompanied with the cryptic message, "hmmmmm."

Conspiracy theorists have long speculated that Klein donated sperm to help Michael Jackson start a family, and Klein has been part of rumors connecting him to Prince Michael in the past,

Prince Michael and sister Paris were both fathered by Jackson with ex-wife Debbie Rowe. Rowe had worked as Klein's assistant at his practice at Beverly Hills previously. Michael Jackson also had a third child, known affectionately as Blanket, who was born by an anonymous surrogate in 2002.

However, despite his apparent hint at being the father with his recent Facebook posting, he has previously spoken out against rumors connecting him to the children. He has said in the past, "To the best of my knowledge I am not the father of these children."

Klein has had a fall from grace in recent years and was forced to file for bankruptcy in 2011. He previously had Cher, Dolly Parton and Elizabeth Taylor as part of his clientele, however, he has since had to sell off numerous mansions in the Los Angeles and Laguna Beach areas after suffering financial problems.

The California Medical Board also moved to revoke his license in 2012 by submitting a request after he refused to submit to a mental and physical examination, according to The Daily Mail.