Charles II (1741-1816) is wearing a steel cuirass (a piece of body armour) and the uniform of a staff officer in the Hanoverian army. Charles was Queen Charlotte's favourite brother and often visited her in England. He was the second son of Charles I, duke of Mecklenburg Strelitz. In 1768, he married Frederica Caroline of Hesse-Darmstadt and he succeeded his elder brother in 1794, becoming Charles II. He became grand duke in 1815.

The miniature is probably based on one of the many portraits of the family by the court painter, Johann Georg Ziesenis, but the identity of the artist is unknown.