The sale this summer by Christie's has been planned in great secrecy and the New York auction house last night refused to confirm it is going ahead. An announcement is planned for early next month.
The sale will put into the shade the sale of dresses of the Princess Diana's dresses which raised just pounds 2m. The Marilyn sale is being organised by Meredith Etherington-Smith, who also masterminded the Princess of Wales' auction. Like that sale, the Monroe collection will also be taken around the world before the auction later in the year.
Among more than 100 lots the skin-tight dress the actress wore when she sang Happy Birthday Mr President to John Kennedy in 1962 is expected to a prize purchase.
The vendor is believed to be Anna Strasberg, second wife of Lee Strasberg, founder of The Actor's Studio at which Monroe trained. When Monroe killed herself in 1962, she left all her possessions to Susan Strasberg, Lee's daughter, who died earlier this year.
Christie's confirmed yesterday that details would be released on June 3. The sale is expected to include private letters and photographs as well as some of Monroe's most famous dresses, movie mementos and jewellery, including a pearl choker.
"We can't say anything about it until June 3," said Vredy Lytsman, spokesman for the auction house. In 1993, 100 items of Monroe's possessions were stolen when they were being kept in storage by the Strasberg family. Police recovered them. At the time, the collection was valued at pounds 6.5m.
But collectors are saddened that the white halter-neck dress worn by Monroe in The Seven Year Itch is unlikely to be in the sale. The dress, which blew up as the actress walked over a street grating, would have fetched a six-figure sum.
The flotsam left behind by the famous has attracted incredible prices. In 1995, Christie's auctioned Frank Sinatra's possessions and realised more than $2m. Among the lots was a piano, which went for $51,750 and a golf cart bearing the legend "Old Blue Eyes" which fetched $20,700.
The dress that raised most for charitywas a number Princess Diana wore at a White House state dinner in which she danced with John Travolta. That went for $222,500.