David Taylor with the Rembrandt painting hanging in the dining room at Buckland Abbey. Photo: Steve Haywood.

LONDON (AFP).- A painting hanging in a British stately home has been confirmed as a self-portrait by Rembrandt worth tens of millions of dollars, the National Trust heritage body announced on Friday.

The picture, which has been at Buckland Abbey in Devon, southwest England, since it was donated to the trust in 2010, was thought for decades to be a portrait by one of the Dutch Master's pupils.

But the world's leading Rembrandt expert has now reattributed it to the 17th-century master himself. It has been given a new value of £20 million ($30 million, 23 million euros) -- though the National Trust said it can never be sold as the organisation holds items on behalf of the nation forever.

"These latest investigations are incredibly exciting and important," said David Taylor, the trust's curator of paintings and sculpture.

"Conservation work and technical analysis being undertaken over the winter will give us further confirmation regarding the picture's authorship."

The self-portrait, dated 1635, shows the artist aged 29 wearing a cap with large white ostrich feathers.

The painting was donated to the National Trust by the widow of a wealthy property developer in her estate.

The painting will hang at the 700-year-old abbey -- which was formerly the home of 16th-century explorer Francis Drake -- for another eight months before being sent for cleaning and further examination.

When it first arrived at the abbey it was kept in storage for 18 months as there was nowhere to hang it, but it now becomes one of the National Trust's most important paintings.

"It's amazing to think we might've had an actual Rembrandt hanging here on the walls at Buckland Abbey for the past couple of years," said Jez McDermott, the abbey's property manager.

"Many of our visitors will have just passed by it, in what is sure to be a real contrast to the attention it is now going to receive." © 1994-2013 Agence France-Presse

Rembrandt discovery at Buckland. Photo: Steven Haywood.

DEVON.- (L-R) House Steward Patricia Burtnyk, Head of Paintings for the National Trust David Taylor, Property Manager Jez McDermot and Conservation Assistant Cirsty Jones hang a recently discovered early self portrait of the Dutch artist Rembrandt at the National Trust property of Buckland Abbey near Yelverton in Devon, southwest England on March 13, 2013. RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT AFP PHOTO / THE NATIONAL TRUST.