Image copyright Duchess of Cambridge Image caption Charlotte was born at London's St Mary's Hospital on 2 May 2015

Princess Charlotte's birthday has been marked with the release of three photographs taken by her mother.

Charlotte, who turns four on Thursday, was captured by the Duchess of Cambridge at Kensington Palace and their Norfolk home of Anmer Hall.

The Duke and Duchess of Sussex sent their best wishes to their niece.

The couple, awaiting the birth of their own child, replied to a Kensington Palace Instagram post: "Happy Birthday Charlotte! Lots of love, H and M."

In one of the new images, Charlotte can be seen in a blue flower-print summer dress as she sits on grass at the palace.

The other pictures show her running and smiling as she holds a flower and sitting on a wooden fence.

Charlotte, who is fourth in line to the throne, was born at St Mary's Hospital in Paddington, west London, at 08:34 BST on 2 May 2015.

Image copyright Duchess of Cambridge Image caption Two photographs were taken at Anmer Hall, on the Queen's Sandringham Estate in Norfolk

The Duchess of Cambridge has released pictures she has taken of her three children on a number of occasions in the past.

Last week, she released three images of her youngest son Prince Louis to mark his first birthday.

And she broke with tradition in 2015 by issuing the official photographs of her newborn daughter.

The series of four pictures were taken just weeks after Princess Charlotte was born and showed her being cradled by her elder brother Prince George.