London, Mar 20 : A rare portrait of William Shakespeare, believed to be the only surviving portrait, could actually be a painting of 17th century courtier Sir Thomas Overbury, claims an expert.

The Jacobean painting from the family collection of art restorer Alec Cobbe was believed to be of the Shakespeare because it closely resembled the engraving in Shakespeare''s First Folio.

However, Dr Tarnya Cooper, the sixteenth-century curator at the National Portrait Gallery in London, has cast doubt on the claims and believes the portrait greatly resembles Sir Thomas Ovebury, an English poet and essayist.

“If anything, both works, the Folger and Cobbe portraits, are more likely to represent the courtier Sir Thomas Overbury,” the Telegraph quoted her as telling the Times.

An authentic portrait of Sir Thomas Overbury (1581–1613) was given to the Bodleian Library in Oxford in 1740, and bears a close likeness to the Cobbe painting.

In both pictures the sitter bears distinctive marks, such as a bushy hairline and a slightly disformed left ear.

However, Professor Stanley Wells, chairman of The Shakespeare Birthplace Trust, is adamant that the painting is of Shakespeare.

"My first impression was scepticism - I am a scholar. But my excitement has grown with the amount of evidence about the painting,” said Wells

"I am willing to go 90 per cent of the way to declaring my confirmation that this is the only life time portrait of Shakespeare. It marks a major development in the history of Shakespearian portraiture," she added. (ANI)