Marilyn Monroe's "Happy Birthday" dress is going up for auction in November (16).
The blonde bombshell sang the tune to President John F. Kennedy at a celebration of his 45th birthday held at Madison Square Garden in New York on 19 May, 1962.
Her breathless version of the song has become world famous, as has the beaded gown she wore for the occasion.
The stunning flesh-coloured Jean Louis dress, which was so tight Marilyn had to be sewn into it, is expected to raise between $2 million (£1.4 million) and $3 million (£2.2 million) when it is put up for sale by Julien's Auctions in Los Angeles on 17 November (16).
Less than three months after Marilyn performed Happy Birthday, she died aged 36, following an overdose of sleeping pills.
The dress was first bought at a Christie's auction 17 years ago by late businessman Martin Zweig, who was so protective of the gown that he kept it in a climate-controlled display case in his penthouse at New York's Pierre Hotel.
"(This dress is) not only Hollywood, but political and historical," Julien's Auctions president Darren Julien told the Associated Press. "She called it (the dress) skin and beads.
"(And because the dress was) was sewn on Marilyn Monroe, Zweig had it professionally mounted on a mannequin. It's never been off it, and is immaculately preserved."
The gown is now being sold by Zweig's estate, as part of a collection of 1,300 pieces of Marilyn memorabilia going up for sale by Julien's.
Among other items up for grabs is the black sequinned dress Marilyn wore in 1959 movie Some Like It Hot.
"This is the last auction of its kind. When she died Marilyn Monroe left everything to Lee Strasberg," Julien explained. "We have the final of his estate items as they relate to Marilyn Monroe. It's literally going to be the last opportunity to ever experience a Marilyn Monroe auction like this again."
Prior to the auction in November, Marilyn's Happy Birthday dress will be on display at Mana Contemporary in Jersey City, New Jersey, from 25 September to 22 October (16), before travelling out of America for the first time to be exhibited at the Museum of Style Icons in Newbridge, Ireland, from 29 October to 6 November.