In the sordid tradition of peddling raunchy video footage of celebrities a la Paris Hilton, a long-buried sex movie of Marilyn Monroe recently hit the market, a top collector told The Post.

An illicit copy of the steamy, still-FBI-classified reel - 15 minutes of 16mm film footage in which the original blond bombshell performs oral sex on an unidentified man - was just sold to a New York businessman for $1.5 million, said Keya Morgan, the well-known memorabilia collector who discovered the film and brokered its purchase.

The footage appears to have been shot in the 1950s. When it came to light in the mid-'60s, then-FBI Director J. Edgar Hoover had his agents spend two weeks futilely trying to prove that Monroe's sex partner was either John F. Kennedy or Robert F. Kennedy, according to declassified agency documents and interviews, Morgan said.

The silent black-and-white flick shows Monroe on her knees in front of a man whose face is just out of the shot.