If what Jack Allen claims is true, then he's made one of the greatest cinematic finds in recent history. Allen, a former TV executive and devoted fan of Hollywood's golden age, perused the online auction site of a recently deceased studio employee in April of 2005, hoping to find a few pieces of classic memorabilia. He believes he found an original, unreleased recording of a song sung by Marilyn Monroe, just as she was poised at the verge of superstardom.

''It was mixed in with some other records, what they call playback records,'' Allen says, ''which are records that film studios produced that artists would then move their mouths to during filming. There was a set from [the 1953 classic] Gentlemen Prefer Blondes, and among them was this record, 'Down Boy.' ''

Allen, who currently runs a digital photo lab in Burbank, Calif., and has produced commemorative books on both Monroe and Bette Davis, speculates that the song was considered redundant with the inclusion of the now-legendary number ''Diamonds Are a Girl's Best Friend.'' Allen contacted actor George Chakiris, who appeared as a chorus boy with Monroe in Gentlemen years before winning an Oscar for his performance in West Side Story; Chakiris confirmed that the number was never actually shot. The song did reappear in 1955's Three for the Show, the little-seen final musical (also choreographed by Gentlemen's Jack Cole) of a then-fading Betty Grable, and its original connection to Marilyn eventually slipped quietly into the movie-trivia ether.

''All the die-hard Marilyn fans have heard of this song,'' says Allen. ''There's a lot of legend encircling her about songs that were supposedly recorded and never filmed, or filmed and cut out, the footage that must exist somewhere, all that.'' Upon receiving the original record, a 78 shellac marked by a faded and yellowed 20th Century Fox sticker set in manual typeface, Allen knew he would need to transfer the recording to something less fragile, stat. "When I got to the studio,'' he says, ''they were afraid to play it, and I had to sign a form. What if it only had one more play in it? But the needle went down, her voice came out, and I just about had a coronary.''

A sweet, playful tune by songwriters Hoagy Carmichael and Harold Adamson — its chorus trills, ''Down, boy/You're actin' like a new foundlin' pup/And mama don't like you jumpin' up. I swear/You gotta stay down, down, down'' — the song does indeed sound like classic Marilyn. And now that the recording is safely transferred to digital, Allen is hoping to get one of her well-known modern fans — among them Gwen Stefani, Mariah Carey, and, perhaps most famously, Madonna — to perform a posthumous duet with the late star, whose 80th birthday would have been last Thursday. With that in mind, Allen has begun contacting a number of celebrity publicists. In the meantime, however, Allen has offered EW.com a clip of the original and a modernized dance remix of the second verse), and asked our readers to say which contemporary singer they'd most like to take on the job. Should it be an updated R&B groove with the Black Eyed Peas' Fergie? An edgier take with snarling pop princess Pink? Or should the original be left as is? You, readers, be the judge.