The walls of the Etruscan dressing room were executed in accordance with Adam's drawings and survive in situ.

There is a preliminary design for the ornamentation to the walls of the Etruscan dressing room in Robert Adam's hand in the National Trust drawings collection at Osterley. There is also an Adam office drawing for the Etruscan dressing room chimneypiece at Osterley, showing the chimneypiece as executed, and as seen in Adam volume 14/130 and 27/73.

Edward Croft Murray has suggested that the painter of the ceiling, walls and chimney board in the Etruscan dressing room was Pietro Maria Borgnis (1743-1810). This is based on a travel account written by Mrs Lybee-Powys, who recounts that the housekeeper at Osterley had said that the walls were painted by 'Berners'. The decoration was painted on to sheets of paper which were pasted on to canvas and affixed to the walls and ceiling.