"Lifeless." "Disappointing." "Ordinary." "Dull." "Old." These aren't normally the words that are used to describe Kate Middleton, the wife of England's Prince William. However, these words are being associated with the Duchess of Cambridge's first official portrait, which was unveiled in London today at the National Portrait Gallery.

The portrait, which was painted by award-winning artist Paul Emsley, shows the 31-year-old royal against a dark background. She is smiling, (or "smirking," according to some critics) and it would seem like her pale complexion brings out the fine lines under her eyes.

Middleton has praised the portrait as "just amazing." Prince William also called the it "absolutely beautiful."

But many have blasted the portrait and accused Emsley of aging the beautiful Duchess's face. "He made her look older than she is and her eyes don't sparkle in the way that they do," said Waldemar Januszczak, art critic for Britain's The Sunday Times. "There's something rather dour about the face."

"Kate Middleton is a pretty young woman with an infectious smile, a cascade of chestnut hair, and a healthy bloom," added Guardian arts writer Charlotte Higgins. "So how is it that she has been transformed into something unpleasant from the 'Twilight' franchise?"

However, Emsley brushed off the criticism and said he followed Middleton's instructions to be "portrayed naturally - her natural self - as opposed to her official self."

The Scottish-born artists doctored the royal's eye color to match her blouse and the painting's background. "She struck me as an 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," he said. 

Middleton sat twice for the portrait, which took three and a half months to complete.

Royal portraits tend to be between the staid and controversial. Queen Elizabeth's 2001 portrait is the most notorious example, with some calling the painting of the monarch as deeply unflattering and others describing it as groundbreaking.  

What do you think about the Duchess's official portrait?