The dress will be part of Julien's three day auction of Marilyn Monroe-related pieces this month and is estimated to fetch £1 610 000-2 417 000 ($2 000 000-3 000 000.)

The custom Jean Louis piece was so tight fitting that Marilyn wore nothing underneath and had to be sewn into it last minute. When Marilyn took to the stage and and revealed the dress, the entire audience gasped.

The song and performance were remembered for many reasons, not the least because it was one of her last public appearances before her untimely death less than three months later. Sadly, President Kennedy died a year later and that infamous night at MSG was the last known time they saw each other.

The infamous performance lasted only 30 seconds, but more than five decades later, it remains the most iconic version of''Happy Birthday'' ever. The dress, the performance, Jacqueline Kennedy's absence and photographs from the evening would spark ravenous rumors of an affair between the President and Marilyn.

''Marilyn Monroe singing 'Happy Birthday Mr. President' is certainly one of the most famous impromptu performances in American history,'' commented Darren Julien, President & CEO of Julien's Auctions.

''That rendition has lived on for decades as one of the most remarkable events in her career and certainly one of the most storied tales in popular culture history — a moment in time squarely at the center of the 1960s, Hollywood and Camelot. We are incredibly privileged to have the opportunity to offer this amazing dress to collectors, fans and contemporary art enthusiasts around the world.''

The dress will be presented on the custom-made mannequin that was designed to match Marilyn Monroe’s exact body measurements. Prior to the auction, the ''Happy Birthday Mr. President'' dress will be exhibited at MANA Contemporary in New Jersey as part of the Exhibition ''Marilyn: Character Not Image'' followed by the Newbridge Silverware Museum of Style Icons (MOSI) in Kildare, Ireland before making its way back to the Julien's Auctions Gallery in Los Angeles where it will be on view from 11th-19th November.

This sale is also timed with what would have been Monroe's 90th birthday.

The Marilyn Monroe auction will take place on 17th-19th November, 2016.