Countess Daisy didn't wear this to the 1897 Devonshire House Ball; she went there playing Marie Antoinette according to the Victoria and Albert Museum. This costume is more like Cleopatra.
This photo shows the Daisy Greville poses in an attention-getting party costume without a distinct waist seam that still shows off her bust and hips. The sleeves are very widely flared as can be seen to the left.
Keywords: Countess Daisy Greville, Countess, British, mistress, Edward VII, jeweled fantasy headdress, vee neckline, long bare shoulder sleeves, flared sleeves, tassels, draped sash, no waistline, tight skirt, bodice ornament, necklace, jeweled straps, wrap