A previously unknown portrait by the Spanish artist Diego Rodriguez de Silva y Velázquez (1599-1660) will be the highlight of the Old Master Paintings auction on Wednesday 7th December 2011 at Bonhams, 101 New Bond Street, London. The work is a portrait of a gentleman, bust-length, in a black tunic and white golilla collar and measures 47 x 39cm. It is estimated to sell for £2,000,000-3,000,000.

Andrew McKenzie, Director of Old Master Paintings at Bonhams, comments, "This is an extraordinarily beautiful portrait which after extensive research we believe to be by the hand of Velázquez. We expect there to be great interest from around the globe as works by this master so rarely come to auction."

In August 2010 a number of works by the nineteenth century British artist, Matthew Shepperson, were consigned for sale at Bonhams Oxford office. Among these works was a portrait of a gentleman, which was brought to the attention of the Old Master Paintings department in London who advised the Oxford saleroom to withdraw it from sale for further investigation.

The stylistic similarities to works by the great Spanish master led to extensive research by the department and consultant Brian Koetser; their views were confirmed by Dr Peter Cherry, Professor of Art History at the University of Dublin and one of the world's foremost authorities on Velázquez and his school. In an article published in the Spanish arts magazine ARS, Cherry writes "the particularized likeness and recognisably lifelike texture, weight and colours of the fleshy face speak of the actual encounter between subject and painter; while the style and technical brilliance of the representation itself betrays its author."

Carmen Garrido, Head of Technical Services at the Prado Museum in Madrid and author of the authoritative work on the artist's technique, Velázquez: Technica y Evolución was consulted about the painting, and technical analysis and an x-radiograph further confirm the attribution to Velázquez.

The identity of the sitter is unknown but it is possible that it could be Juan Mateos, Philip IV's Master of the Hunt.

Andrew McKenzie comments, "Velázquez is one of the greatest geniuses in the entire history of Western art. 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."