A sketch that Christie's recently sold for £3,500 ($5,326) as by a "follower of John Constable" has been revealed as a preparatory work for his famous Salisbury Cathedral from the Meadows, which hangs in London's Tate Museum.
It will now sell at Sotheby's New York on January 29, valued at $2m-3m.
The oil sketch sold in July 2013, estimated at just £500-800. It was snapped up by an unnamed buyer, who spotted that the piece had been retouched at the turn of the 20th century.
After the work was cleaned, it was then examined by experts on Constable, who attributed it to the artist himself and dated it to 1829-1830. It is thought to be one of the final preparatory sketches for the painting, which the Tate bought for £23m ($35m) in 2013.
The sketch was brought to auction from the family of Viscount Hambledon, who sold a large amount of art and antiques through Christie's in 2013. The sale also presented a work that was listed as "after Claude Lorrain" at £15,000-25,000 but was soon pulled from auction and later authenticated as a genuine piece and sold for £5m ($7.6m).
The news comes following the Victoria and Albert Museum's discovery of a previously unrecorded oil sketch by Constable concealed beneath the lining of a painting of Hampstead Heath.
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