Kate spent time calling photographers and subjects of images which were part of her Hold Still project, ahead of the book's release this week.
In one call, four-year-old Mila Sneddon asked if the duchess was wearing a costume, and Kate said she was not in her princess dress, but promised to find one before they met.
Mila had to isolate away from her father for several weeks when he was still working because she was undergoing chemotherapy for leukaemia.
They were reunited when he was furloughed.
