Considered one of the most recognisable costumes in movie history, the iconic ivory gown far exceeded sales expectations, according to Reuters. The dress was originally estimated to sell for only $1 million to $2 million (£618,000 to £1.2 million).
Monroe wore the dress in a scene in the 1955 movie in which the actress stands above a subway grate as a passing train raises it around her head.
The auction was held by actress Debbie Reynolds, who began collecting movie costumes in earnest in 1970. Reynolds planned to display the outfits in a museum, but was eventually forced to sell them in order to pay back creditors.
"Now everyone has the opportunity to own them," Reynolds said.
Other costumes that were sold included Monroe's red-sequinned dress from Gentlemen Prefer Blondes, Audrey Hepburn's Ascot dress from My Fair Lady, Judy Garland's blue cotton dress from The Wizard of Oz and Mike Myers's orange suit from Austin Powers: The Spy Who Shagged Me.
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