The black Givenchy dress worn by Audrey Hepburn in the film "Breakfast at Tiffany's sold at auction Tuesday for $807,000.
The price, paid by a telephone bidder, was almost six times the highest pre-sale estimate.
The iconic garment had been expected to fetch between $98,000 and $138,000 as part of a sale of film and television memorabilia at Christie's auction house in London.
Proceeds from the sale will go to the charity City of Joy Aid, which helps India's poor.
Hepburn wore the dress for one of her best-known roles, as eccentric Manhattan socialite Holly Golightly in the 1961 film adaptation of Truman Capote's novel.
The opening scenes of the film show Golightly in the dress emerging from a taxi on 5th Avenue with her brown-bag breakfast to ogle diamonds and luxury goods in the storefront windows of Tiffany & Co.