The first official portrait of Kate Middleton has been revealed today (11 January).

The Duchess of Cambridge, who is expecting her first baby with husband William this summer, is slightly smiling in the painting by artist Paul Emsley.

He had two sittings with the 31-year-old royal and was asked by her to be portrayed in a natural light, rather than her official self.

The portrait will go on display from today at London's National Portrait Gallery, of which Kate is a patron.

Kate studied history of art at St Andrews University and is understood to have been involved in selecting Paul as her painter, along with the gallery's director Sandy Nairne.

Paul, who specialises in strong, contemporary and simple portraits and whose previous subjects include Nelson Mandela, described Kate as "enormously open and generous and a very warm person."

See the portrait, below.

Picture credit: Rex Features

Official portrait of Kate Middleton unveiled