A London museum says it has discovered a previously unknown oil sketch by John Constable tucked beneath the lining of another work by the English romantic painter known for his landscapes.

The Victoria & Albert Museum said Tuesday that the sketch of trees underneath an unsettled sky was most likely painted in 1821 or 1822.

The museum said it was discovered when conservators at the museum attempted to remove the lining on the back of Branch Hill Pond: Hampstead while preparing for a 2014 exhibition, Constable: The Making of a Master.

The previously unrecorded work will be put on display at the Victoria & Albert Museum on Wednesday.

Constable died in 1837. His daughter gave the museum the remaining contents of his studio in 1888.