John August, the second surviving son of Frederick II, Duke of Saxe-Gotha and Magdalena Augusta of Anhalt-Zerbst, was brother to Augusta, Princess of Wales.

Although the label on the painting identifies the sitter as Prince John (or Johann) August of Saxe-Gotha, it is possible that it depicts his younger brother, Prince Johann Adolf (1721-99). The latter was painted by Charles Philips on his visit to England in 1742 (RCIN 407543). He is shown wearing armour, with an ermine-lined crimson mantle draped over his left shoulder and wearing a powdered wig; he is carrying a baton in his right hand.