Princess Charlotte celebrated her 9th birthday on Thursday with the release of a photograph taken by her mother, Kate Middleton.

Earlier this week, the Princess of Wales took the picture of her daughter in the gardens of their Windsor home, in a sign that she is doing well as she undergoes cancer treatment.

In a touching tribute, Charlotte was photographed next to Clematis Elizabeth flowers, which are named after her great-grandmother, the late Queen Elizabeth.

Kensington Palace released the image via its social media channels, a new way of distributing the Prince and Princess of Wales’ pictures, enabling the couple to issue pictures when they want. “Happy 9th Birthday, Princess Charlotte! 🎂 Thank you for all of the kind messages today,” read the photo caption.

Kate has traditionally photographed her children to mark milestone moments such as birthdays. She prefers to shoot the children outside in nature and the image of Charlotte shows the princess leaning against a fence outside, dressed in a denim skirt and cardigan.

Charlotte, who is third in line to the throne, was at school on Thursday but is expected to celebrate her special day with her family over a special birthday tea. Kate has revealed how she sticks to a family tradition of baking a cake for every one of her children’s birthdays and it is likely that Charlotte, who is outgoing and popular at school, will also have a party to celebrate with her friends.

Prince William and Kate are said to be doing everything they can to keep things normal at home while the Princess of Wales undergoes preventative chemotherapy. The couple’s official work schedules are planned so that either Kate or William can do the school run, and one of them is home when the children get back from school.

Prince William revealed during an engagement this week that the family was “doing well” after a well-wisher inquired about Kate.

The fact that Kate photographed Prince Louis – who turned six last week – and Charlotte this week is an indication that she is doing well, sources say. Following the fallout over her digitally manipulated Mother’s Day image, Kensington Palace pointed out that the photo of Charlotte had not undergone any digital retouching.

“The princess loves taking pictures of her children and knows it gives the public great pleasure too, she intends to keep doing so,” says a royal source. “She considers herself very much an amateur but she enjoys this new tradition of royal photographs.”

On Thursday, the couple’s wedding photographer Millie Pilkington commented on the image, describing Kate as “talented” and wishing Charlotte a happy birthday.

Earlier this week, a new photograph of William and Kate on their wedding day taken by Pilkington was released on the Wales’ social media channels to mark their 13^th wedding anniversary.