The royal may have just given birth to her little princess, Charlotte, but the new mum shares her passion for this worthy cause.
And with two children of her own, it's easy to see the 33-year-old is speaking from the heart throughout the profound message that she penned on behalf of Children's Hospice Week.
"For families of children with life-limiting conditions, every moment is precious and every memory needs to be cherished and celebrated," Kate explained in her note.
"Children’s hospices strive to create happy moments in the most difficult times any family could face. I hope you will join me in supporting Children’s Hospice Week and work to make every moment count for all of our families.”
Kicking off this week right through to Mary 17, Children's Hospice Week will raise awareness with a week-long fundraiser aimed to help ensure parents of children with life-limiting illnesses have the support they need to make the most of every minute they have left.
Last November, while Duchess Catherine was a patron for East Anglia’s Children’s Hospices, she saw firsthand the invaluable work Children’s Hospice does from families.
At the time, the empathetic royal, who was pregnant with her second child, broke down after one woman shared her heartbreaking story.
Leigh Smith, 33, opened up to the Duchess about how she lost her 3-month-old daughter Beatrice last February, after suffering from a heart condition called cardiomyopathy.
"I wrote to Kate after Beatrice's death to tell her about the amazing support I'd received from EACH," Leigh told reporters at the event.
"She wrote a personal letter back to me saying what an honour it was to hear my story. I thought that was so lovely as obviously it was such an honour to hear back from her. She said she was very touched to hear Beatrice's story."
Leigh recalled at the event Catherine hugging her and saying, “You're a very brave lady — I'm just so, so sorry.”
The charity is urging people to support the week by sharing a memorable moment on social media using the hashtag #momentscount.