In return, Meghan picked a white rose from the bunch for the youngster.
For the second time in a week, Meghan has rocked a chic ensemble - this time to the WellChild Awards in London with husband Prince Harry.
The duke and duchess will attend a pre-ceremony reception and meet the young winners of each award category and their families, and the nominated healthcare professionals. "They were both so nice", Matilda's mother, Sharon Booth, told reporters, according to People.
The WellChild Awards are an annual ceremony recognizing the bravery of seriously ill children and their caregivers.
Mrs Booth said the royal urged her daughter, who wants to be a nurse, to "never stop smiling as you've got a handsome smile".
In the photo, Meghan goes makeup-free and wears her hair scraped back into a scruffy top-knot (yes, Meghan is JUST like us), while Rylan looks adorable in a fairy costume.
The former actress has previously frequented pant suits in her royal career.
Meghan was introduced to Harry by a mutual friend in July 2016, and the pair were married on 19 May this year, Express reports.
He was given the most caring young person award for helping to look after his sister.
In a foreword for the event's official programme, he wrote: 'This evening, we are celebrating remarkable stories of hope, resilience and selflessness.
"Every one of you is truly unbelievable".