William's touching tribute was accompanied by a new photo of the Princess of Wales dressed in jeans, a blouse, blazer and checked scarf. The black-and-white photo of Her Royal Highness smiling with her hands in her pockets was taken by Matt Porteous last summer in Windsor.

Catherine, Princess of Wales, turned 43 on Thursday, with her husband Prince William praising her "strength" fighting cancer during the past year. Kate, as she is widely known, revealed last March that she had been diagnosed with an unspecified cancer and was undergoing chemotherapy.

The Prince of Wales shared a new picture and described his wife as 'remarkable' in a touching birthday tribute on Instagram.