The outfit Joan Collins wore on becoming a dame at Buckingham Palace has sold at a US auction for more than $23,979.

The cream dress, cape and black belt were designed by Dame Joan herself and the outfit had been expected to fetch between $5,000 and $6,000 but bidding reached $25,600.

A collection of items, including love letters from Warren Beatty and costumes she wore on Dynasty, was sold at Julien’s Auctions in Beverly Hills, California.

The 82-year-old actress also parted with fox and mink furs, costume jewellery, furniture and couture gowns, with the sale raising hundreds of thousands of dollars, according to the auction house.

The two love letters from Beatty are dated 1960, when the couple were engaged and he was doing national service. The letters, which are part handwritten and part typed, are in their original envelopes and addressed to Miss Joan Collins at addresses in Rome. In one he addresses her as “bird” and lists his return address as Beverly Hills, California.

The letters, which are accompanied by a playbill from Beatty’s first play and a photograph of the couple, reached pre-sale expectations, selling for $1,920.

Dynasty fans who fondly remember her as Alexis Carrington Colby jumped at the chance to snap up some of her costumes from the cult show, including a red gown and cropped jacket, which sold for $6,875. A Joan Collins Kenneth Lane necklace worn on the show sold for $9,375 and a Louis Vuitton trunk went for $8,750.

In a separate auction at Julien’s, Marilyn Monroe’s certificate of conversion to Judaism fetched $68,750 and a cast of her hands and feet sold for $56,250.