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.

Princess Kate reportedly made a secret visit to the Royal Marsden Hospital in London, where she previously underwent chemotherapy treatment, before Christmas. The Princess of Wales, 43, made her first solo public engagement in more than a year on January 14,

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

Everyone just noticed that Kate Middleton isn't wearing her engagement ring...here's what we know about why she ditched the iconic sapphire.

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.

Kate Middleton made a surprise visit to the Royal Marsden Hospital where she received cancer treatment, following her diagnosis last year.

Princess Kate made her first solo official appearance in more than a year as she visited the Royal Marsden Hospital in London to thank staff for her care

Kate Middleton just became an official patron of the hospital where she received preventative chemotherapy treatment, marking her first royal engagement of the year. During the outing, Kate visited with patients at the Royal Marsden Hospital,