Kate Middleton made a visit Tuesday to the Royal Marsden Hospital in London, where she underwent cancer treatment last year.

During the outing, which was her first solo engagement in over a year, she also announced that she is to become joint patron of the Royal Marsden alongside her husband, Prince William. William inherited the role from his mother Princess Diana.

As she entered the hospital bundled against the winter chill in a burgundy turtleneck and skirt, Princess Kate was overheard commenting that it was nice to come in the front entrance “having made so many quiet private visits.”

While meeting with one cancer patient, who was wearing a cold cap to prevent hair loss, Kate asked, “When did you first start treatment? Oh, today? How are you finding it?”

Like King Charles, who visited a cancer center to mark his return to official duties last year, Princess Kate wants to use her profile to spotlight a cause that is now close to her heart.

A spokesman said, “The Princess wanted to make the journey to both show her gratitude to the incredible team, but also highlight the world leading care and treatment the Marsden provides.”

It is understood that Tuesday’s visit is one of a few carefully chosen engagements as the princess plans a “gradual return to work,” according to her aides.

According to sources close to the princess, Kate was keen to go back to the hospital where she was treated so that she could thank the staff for their amazing care and to show her support to some of the patients currently undergoing treatment.

Kate has spoken movingly about how she plans to support others going through their own cancer journeys in the future. While the princess’s recovery is ongoing, when she announced she had completed chemotherapy, she vowed to support others diagnosed with cancer, saying, “To all those who are continuing their own cancer journey – I remain with you, side by side, hand in hand. Out of darkness, can come light, so let that light shine bright.”

The Royal Marsden is a world-renowned cancer care and treatment center that plays an important role in advancing treatment and pioneering research. Until now Kensington Palace has chosen not to disclose where the princess was treated but on Tuesday, Kate revealed that she had made a number of private visits to the Marsden. As co-patron of the hospital alongside Prince William, the princess will support the work of the Marsden as well as learn more about how it can benefit patients in the future.