How the Duchess of Cambridge is preparing to be Queen while becoming one of the monarchy's greatest assets

The Duchess of Cambridge has come a long way since she was first introduced as the girlfriend of Prince William more than a decade ago.

Now, with 10 years of royal service under her belt Catherine, formerly Kate Middleton, is shaping up as a formidable force in the British royal family.

January 9 marks the duchess' 40th birthday, and the occasion is expected to be marked in quiet discretion — just how Kate has slowly carved out a role for herself in the monarchy.

READ MORE: New photos of Prince William and Kate released to mark their 10th wedding anniversary

Taking cues from the Duke of Edinburgh, who was by the Queen's side for 73 years, the Duchess of Cambridge has always known her place as the wife of the future King.

But far from staying in the shadows, Kate has emerged as a powerful player in the royal family.

It will likely be many years yet before the Duchess of Cambridge assumes her position as Queen Consort alongside her husband, King William V, but after more than a decade in the royal spotlight she's proven herself one of the monarchy's greatest assets.

From the early days of being criticised for not working hard enough to spearheading one of the biggest projects to improve the outcomes for children, Kate's causes are those that are most meaningful to her.

Mental health, early childhood development and the benefits and importance of nature are all Kate's passions and will remain key areas of focus as her role within the royal family increases.

But it was Kate's photography project started during the height of the coronavirus pandemic lockdowns that will see be one of her greatest crowning achievements.

To see Kate's rise from middle class schoolgirl to future Queen, watch the video above.