Oil on canvas, 127cm by 100.3cm. Inscribed l.l. with the identity of the sitter and dated 1775.
Gainsborough was a founder member of the Royal Academy and one of the greatest and most successful portrait painters of the 18th Century.
Lady Whichcote was an ancestor of Isabella Whichcote of Aswarby Park, Lincolnshire who married Lord Burghley in 1875. He would become the 4th Marquess of Exeter on the death of his father in 1895.