Wilhelm designed many productions for Adeline Genée, star dancer at the Empire Theatre music hall in the 1890s and early 1900s. Among his last work for her was the ballet The Pretty Prentice, the purpose of which was to show Genée as a mischievous shop girl in as many different moods as possible. This extraordinary creation which he entitled Eccentric Dress is the ultimate Edwardian dance dress, blending imagination and character. A fun dress for a fun character. The stylised feathers on the skirt, to be executed in coloured fabrics, silver and sequins, complement the ostrich feather headdress, while the sequinned bodice with its enveloping snake, contrasts with the silver and rhinestones and the stiff, pleated 'epaulettes' on the shoulders. The silver pantaloons add a delicious touch of naughtiness, so characteristic of the lost Edwardian period.

Wilhelm worked in the prevailing style of late 19th century realism, but with an imagination and flair and knowledge of his subject that made him outstanding. What makes this design extraordinary is the definition and precision of the drawing, and how Wilhem conveys in paint the final effect of the costume - whether a flower or sparkling sequin snake; he suggests the fabrics, the density of velvet, the sparkle of sequin, the soft floating of silk. It was his knowledge of the techniques of stage costume making, and how to use materials, that made Wilhelm supreme among stage designers.