Set between the second drawing room and the Etruscan room, the small circular ante room is another example of Adam’s extraordinary attention to detail. He produced drawings for the dome ceiling and the chimneypiece with its overmantel mirror frame, both of which were designed to fit the room’s curvature. As with the other frames designed for the house, the overmantel does not survive, but the ceiling and chimneypiece remain in situ.
Harris notes the room’s relation to the semi-circular porch beyond, and highlights contemporary references to the ‘Belvedere’. She notes how the opening of the room on to the porch would have provided views of the garden and fields beyond.