Throughout his presidency and his marriage to Jackie Kennedy, JFK was known as a playboy.

But stories about his swinging lifestyle, including his alleged affair with Marilyn Monroe, have mostly been hearsay.

Four decades after his death, TMZ has obtained a photograph that forensic experts suggest may prove President John F. Kennedy's libidinous appetite.

The never-before published black-and-white photograph, which TMZ believes was taken in the mid-1950s, shows a man who appears to be Kennedy lying in the sun below the boat's top deck. Above him, two naked women sun themselves while another couple of nude ladies jump off the boat.

Multiple experts who examined a scan of the original print concluded that the photo appeared authentic. TMZ reports that no evidence of Photoshopping was found after the experts studied the image for inconsistent lighting, photo composition and other forms of manipulation.

Forensic photo expert Prof. Jeff Sedlick told TMZ that the actual print appears authentic as well. He says the paper on which the photo is printed appears consistent with the brands used in the '50s. The print's emulsion includes cracks that seem to have developed over time.

Sedlick also superimposed on the photo an image of Kennedy taken at the Democratic National Convention in August 1956. Taken just days before he embarked on his Mediterranean cruise, the convention photo's features match those of the new yacht image, Sedlick says.

Two Kennedy biographers have also told TMZ that after examining the image, they believe the man to be JFK.

Although the photo's original owner has not been revealed, the image was eventually given to a man who owned an East Coast car dealership. TMZ reports that the man kept the photo in a drawer and would take it out to brag to friends. After the man died a decade ago, his sons inherited the photo.

Several books and articles have reported that in August 1956, Kennedy spent two weeks on a boating trip in the Mediterranean. A senator at the time, Kennedy was vacationing with his brother Ted Kennedy and Sen. George Smathers. The three men allegedly invited a number of women on the yacht.

Meanwhile, a pregnant Jackie Kennedy was rushed to hospital and underwent an emergency Caesarean section. Unfortunately, the baby was stillborn.

If the photo had emerged when Kennedy ran for President in 1960, his image as a wholesome family man would have been destroyed and his chances to run America probably would have vanished with it.