Diamond Marshall met Kate, 29, as she arrived by helicopter in Calgary, Alberta — the final stop on their nine-day tour of Canada.
The Duchess of Cambridge brushed off fears of an embarrassing wardrobe malfunction, as her skirt was whipped up by the wind, to warmly embrace the six-year-old on the tarmac.
The youngster, who has a large tumour in her abdomen, raced to hand over a bouquet and flew into Kate's arms.
Her stepmother Danielle Marshall, 32, said: "Kate was lovely, they were so gracious and spent extra time with her. For a little girl who dreams everything princess, it was a dream come true."


Diamond had revealed she would love to meet Kate after watching the royal wedding from her hospital bed.
So dad Lyall Marshall, 37, wrote to the Children's Wish Foundation of Canada in the hope they would be able to help.
Luckily the royal couple were on hand to make her dream come true.

The couple had earlier taken a day off from their tour to enjoy a picnic in a remote, idyllic spot.
The Prince, 29, arranged the treat at a hikers' lodge deep in the Canadian Rocky Mountains.
There they enjoyed some of the world's most breath-taking scenery, sheer rock cliff peaks that lead down to turquoise, glacier-fed lakes, and natural ever-green forests.