A painting first valued at £300 is expected to fetch up to £3 million when it goes under the hammer at Bonhams this week after it as discovered it is by Velazquez.
The portrait of an unknown man is part of an auction of works by British painters and old masters, Reuters reported.
It could soon become popular on canvas prints as well – a far more affordable option for art lovers.
The painting features a balding man in a black tunic with white “golilla” collar and was part of a collection of works attributed to 19th century British painter Matthew Shepperson.
It was due to be sold at Bonhams in Oxford but the auctioneer suspected it was by a different artist and sent the piece to the Old Master Paintings department in London.
Consultant Brian Koetser and history of art lecturer Peter Cherry, one of the world’s authorities on Velazquez, confirmed it was by the Spanish painter.
They dated it between 1631 and 1634, when Diego Velazquez was in Italy or shortly after he returned to Spain.
Just 100 pieces are known to exist and a handful are still in private collections.
“The discovery of this lost treasure is a once-in-a-lifetime experience and it is tremendously exciting to be able to bring it to the world’s attention,” Andrew McKenzie, director of old master paintings at Bonhams, told Canvas Prints.
Sothebys is also hosting its main London sale of old master and British paintings, where The Card Players in an Interior by 17th century Dutch artist Jan Steen is expected to be the top lot with an estimate of £4.5 to £6 million.
Canvas Prints can also report that a pair of works by the 18th century painer Johann Zoffany commissioned by British actor David Garrick are also going under the hammer, with Sotherbys expecting to raise more than £21 million.
Art fans without spare millions in the bank can opt for canvas prints to adorn their walls instead.