The figure-hugging gown Marilyn Monroe wore to serenade US President John F. Kennedy on his 45th birthday smashed its guide price to sell for $4.8 million at auction on Thursday.

The flesh-colored dress, adorned with 2,500 hand-stitched crystals, had been expected to fetch between $2-3 million, Julien's Auctions in Beverly Hills said.

It went to Ripley's Believe It or Not!, an American media empire specializing in bizarre and historically significant items which owns a chain of museums, including one in Hollywood.

The dress was so tight on Monroe that the legendary actress wore nothing underneath and had to be sewn into it at the last minute before stepping on stage at Madison Square Garden in 1962 to sing to JFK in her trademark sultry voice, according to the auction house.

First auctioned by Christie's in 1999, the Jean Louis dress went to the late business mogul Martin Zweig for $1.3 million. "Marilyn Monroe singing 'Happy Birthday Mr. President' is certainly one of the most famous impromptu performances in American history," said Darren Julien, president and CEO of Julien's Auctions.

"Tonight was one of the most important moments in our history as a company. We were incredibly privileged to have had the opportunity to offer this amazing dress from the most legendary screen star of all time."

Monroe died of an overdose less than three months after the performance, while Kennedy was murdered a year later.

Other highlights of the first day of the three-day auction of Monroe's personal effects included the Some Like it Hot cocktail dress which sold for $450,000, and a Rose Tattoo gown which went for $125,000.

A pair of her Ferragamo shoes were snapped up for $34,000 while the her Niagara negligee went for $59,000. Such was the popularity of the Mr. President gown that even a sketch of it by fashion designer Bob Mackie sold for $10,000.

Marilyn Monroe's 'Happy Birthday Mr. President' gown Reuters