Kate Middleton looks like she has had one too many sleepless nights in the first official portrait of her.

Bags hang under her eyes and she appears to be trying hard to not doze off in Paul Emsley's rendering for the National Portrait Gallery.

Prince William's wife smirks sardonically from the picture against an eerie black background. The mother of the future King or Queen of England would not look out of place next to R-Patz and K-Stew in vampire franchise, Twilight.

Emsley said he was not trying to paint a typical portrait of a royal.

"The duchess explained that she would like to be portrayed naturally - her natural self - as opposed to her official self," said Emsley.

"She struck me as enormously open and generous and a very warm person. After initially feeling it was going to be an unsmiling portrait I think it was the right choice in the end to have her smiling - that is really who she is."

Painting Kate could have been a tough assignment because the duchess has a degree in art history from the University of St Andrew, where she met Prince William.

A spokeswoman for Buckingham Palace said the duchess was pleased with the result. "She very much enjoyed working with the artist and the gallery for the portrait," she said.

Deep lines on Kate's face and bags under her eyes are drawn out by how the image is lit. By lighting Kate sharply against a background in darkness, Emsley is employing the Renaissance painting technique of chiaroscuro. In this case, however, critics say the effect is more akin to something from a cheap ghost story.

Adding to the unsettling atmosphere is the soft-focus tinting, possibly a result of Emsley's painstaking process of building up thin layers of oil and glaze.

It is not the first time that elements of the gothic have been (mis)matched with the Duchess of Cambridge. When her wedding dress went on display, it was presented in a funereal setting of high-contrast lighting at Buckingham Palace. The garment by Alexander McQueen appeared to be levitating towards the viewer as if it was animated by a paranormal presence.

However, while this new portrait is out of place in the traditional cannon of idealised Royal images, perhaps Emsley's painting is in tune with the anxious times in which Duchess Kate finds herself the focus of many hopes and expectations.

Written by Dominic Gover