Marilyn Monroe's iconic dress just broke a world record for being the most expensive dress ever sold at auction, with a price of $4.8 million. The legendary actress and model wore the dress on U.S. President John F. Kennedy's 45th birthday where she serenaded him with a song called "Happy Birthday Mr. President."

The much talked about dress features over 2,500 hand-stitched crystals. The personalized Jean Louis gown was reported to be so tight that Monroe had to be sewn into it. The sheer, nude-colored gown had a previous estimate of $3 million before it went under Julien's auction house in Beverly Hills.

Julien's Auctions' executive director, Martin Nolan stated that the dress represents a momentous occasion that also served as "a defining moment in history." According to him, the actress' rendition to the late president is one of the most remarkable events in Monroe's career and definitely one of the favorite tales in pop culture history.

The "Happy Birthday" dress was presented and placed in a mannequin that had the exact measurements as Monroe's. The item was then bought by Ripley's Believe It or Not museum chain. The show's vice president, Edward Meyer, released a statement about the dress.

"We believe this is the most iconic piece of pop culture that there is," he said. "In the 20th century I cannot think of one single item that tells the story of the 1960s as well as this dress. It's a new world record for a dress."

This record-breaking sale surpassed the former dress that had the title of being the most expensive dress sold, Monroe's "The Seven Year Itch" white costume which was sold at $4.6m in 2011. Monroe's "Some Like it Hot" cocktail dress was also sold for $450,000 on Thursday. Most of the actress' personal possessions including her beautifully designed clothes were handed down to Lee Strasberg.

The most expensive dress ever sold at auction had been worn by Monroe during one of her last public appearances before she was found dead from a drug overdose months later.