The Prince and Princess of Wales have released a new photograph of Prince Louis to mark his sixth birthday

Catherine, 42, and Prince William, 41, have also thanked members of the public for their special "wishes" for their son.

The couple captioned the post on their official Instagram page: "Happy 6th Birthday, Prince Louis!

Thank you for all the kind wishes today."

Following the debacle over a photograph that the royal admitted she edited of her with her three children - also including Prince George, 10, and eight-year-old Princess Charlotte - the Palace has said the new picture of Louis has not been altered.

Catherine issued an apology to clear up "confusion" over her Mother's Day picture.

After she found herself at the centre of a debate over the photograph it was withdrawn from circulation by several picture agencies amid concerns it had been altered - and Catherine said she was sorry and admitted she "occasionally" dabbles with "editing" her snaps.

A statement released by the princess explained: "Like many amateur photographers, I do occasionally experiment with editing.

"I wanted to express my apologies for any confusion the family photograph we shared yesterday caused. I hope everyone celebrating had a very happy Mother's Day. C."

It was the first official picture of the royal since she underwent surgery in January and stepped away from the spotlight during her recovery.

Catherine later revealed she has cancer as speculation grew about her stepping out of the spotlight and is continuing to receive preventive treatment.

The mum-of-three announced in March she was undergoing treatment after doctors detected cancer in her body following her major abdominal surgery in January at The London Clinic, the same private hospital King Charles, 75, is receiving treatment from for an undisclosed form of cancer.