PHOTO: Palace releases 3 portraits of Duchess Kate Middleton to mark her 40th birthday

London: Duchess of Cambridge Kate Middleton on Sunday celebrated her 40th birthday.

They also shared throwback pictures of the Duchess with her family and Queen Elizabeth II.

To mark her birthday, three new photographs of the Duchess of Cambridge were released with the caption, "Delighted to share a new portrait of The Duchess ahead of her 40th birthday tomorrow. This is one of three new portraits which will enter the permanent collection of the National Portrait Gallery, of which The Duchess is Patron."

The portraits, taken by fashion photographer Paolo Roversi, show her wearing different Alexander McQueen dresses.

In one of the photos, Kate can be seen in a white gown. In another photo, she wore red gown, earrings loaned by the Queen and some belonging to Diana, Princess of Wales, in the other two, BBC reported.

The three portraits were taken at Kew Gardens in November. They will be part of a project from the National Portrait Gallery where the duchess is patron.

Portraits will be on display this year in Berkshire, St Andrews and Anglesey. These locations have been chosen by the Duchess as they have special meaning for her.

BBC quoted fashion photographer Paolo Roversi as saying that taking a portrait of the Duchess was a "true honour" and "a moment of pure joy". (UNI)