The ante room was located on the first storey, at the front of the house behind the two left-hand bays, above the hall, and between the staircase and the first drawing room. A plan of the house can be found in The works in architecture of Robert and James Adam (Volume II, part 1, plate 1).

There were two spaces at 23 Grosvenor Square to which Adam gave the name ante room: one being the ante room to the eating parlour on the ground storey, and this room on the first storey. This design for a ceiling can be firmly attributed as intended for the first storey ante room through comparison of its dimensions with those shown on Adam's plan in the Works.

As the house was demolished in 1862, and this ceiling is not illustrated in the Works, it is not known if the ante room ceiling was executed in accordance with Adam's extant design.