The Duke and Duchess of Cambridge, Prince William and his wife Kate, have released a rare photograph of their daughter Princess Charlotte to mark the second birthday.

The toddler princess is pictured at their Norfolk home, Anmer Hall, wearing a yellow cardigan decorated with images of sheep, while she sports a navy clip in her hair.

In a statement Kensington Palace said: “The Duke and Duchess are very pleased to share this photograph as they celebrate Princess Charlotte’s second birthday.

“Their Royal Highnesses would like to thank everyone for all of the lovely messages they have received, and hope that everyone enjoys this photograph of Princess Charlotte as much as they do.”

Charlotte’s privacy has been carefully guarded by her parents and during the past year she has only been seen in public on a handful of occasions.

Charlotte is the Queen’s fifth great-grandchild. The Queen is known to Charlotte and her brother George as “Gan Gan”.

She is fourth in line to the throne following the Prince of Wales, the Duke of Cambridge and Prince George.

Charlotte is the highest ranking female in line to the throne, followed by Princesses Beatrice and Eugenie who are seventh and eighth in line.

– With AAP.