The apsidal third drawing room was located on the principal (first) storey, in the north-west corner of the house facing the square.

All of Adam's interior decorative schemes for 20 Soho Square are thought to have been executed, but this is speculative as it was largely redecorated during the nineteenth century. It is likely, however, that this design for the ceiling was executed as the inset paintings survive, having been removed in 1906 (see scheme notes).