Dated to c.1777-80, Gypsy Encampment, Sunset will be offered as a fully authenticated sketch by Thomas Gainsborough at their sale on July 2.
An inscription on the verso states it was given by the artist to the portrait miniature painter Ozias Humphry and then passed to his son William Upcott, a librarian and antiquary who amassed a large collection of Gainsborough drawings.
Bequeathed by Upcott to his friend Charles Hampden Turner, it thereafter descended through his wife's relatives (the Wigram family) to the vendor here.
An estimate is £20,000-30,000.
Tel: 01895 621991.