Kate Middleton didn't wear her engagement ring that once belonged to Princess Diana at the Royal Marsden Hospital in London on Jan. 14. Inside why and more about Princess Kate's new ring.

For her first official solo appearance in over a year, Princess Kate met with cancer patients and the team at London's Royal Marsden Hospital.

Kate, the Princess of Wales, made a poignant return Tuesday to the same hospital where she received treatment after being diagnosed last year with cancer.

Kate Middleton visited the Royal Marsden Hospital in London on Tuesday, Jan. 14, where she received chemotherapy treatment after her cancer diagnosis last year. See all the photos here

The Princess of Wales made a surprise return to the Royal Marsden Hospital to personally thank staff who looked after her during her cancer treatment on Tuesday. At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story.

The Princess of Wales was visibly moved by a remark about her three children during her recent visit to the Royal Marsden Hospital

Kate Middleton opted for one of her go-to colors during a visit to The Royal Marsden Hospital in London on Tuesday. The Princess of Wales and her husband, Prince William, are joint patrons of The Royal Marsden NHS Foundation Trust. Middleton received treatment from The Royal Marsden during her battle with an undisclosed form of cancer.

Pretty much every second of Kate's visit was analyzed, and fans just noticed that she wasn't wearing her iconic diamond and sapphire engagement ring. But real quick before you sta

Middleton’s famous 12-carat diamond and sapphire engagement ring (you know, the one that used to belong to Prince William‘s late mother, Princess Diana) was MIA. And yes, this

Princess Catherine just made her first royal outing of the year—and this one hits pretty close to home. Earlier today, Kate Middleton paid a visit to The Royal Marsden, which happens to be the same cancer treatment center where she received her chemotherapy treatments following her cancer diagnosis.