Mia was diagnosed with Batten Disease when she was 4, and her family has documented her journey on a website and social media pages to raise awareness for the rare disease that left Mia unable to walk or talk.
The little girl met Kate when she and Prince William visited the children’s hospice Bear Cottage during their 2014 tour of Australia.
Mia's mother, Peta, wrote on their website, Bounce 4 Batten, 'Kate sailed into the garden gracefully and joined in singing ‘Twinkle Twinkle Little Star’ and we watched enraptured as she interacted with the children.
'She made her way around the group meeting each family and chatting. She listened so attentively to us and crouched down engaging with Mia which was very sweet and probably not very comfortable.
'Mia said the word ‘baby’ and Kate replied ‘yes, I have a baby, baby George'.'
The family also met Prince William, who approached Mia’s father during the hospice visit.
'My husband was tapped on the shoulder only to turn and be face to face with Prince William,' Peta recalled on her website. ''You must be Hamish, Mia’s father?’ William was personable and engaging and complimented Mia on her beautiful princess dress. It was a beautiful sunny day and we will cherish forever meeting the Duke and Duchess at Bear Cottage.'