Yesterday, he got the chance to meet the children's group when they performed in Dunedin.
His mother Mel said her son was "so stoked'' to meet his "heroes''.
The meeting, which took place before the performance, was organised by a radio station.
Charlie's surgery in May this year was his third such procedure to "replumb'' his heart.
The first procedure was as a newborn.
Charlie has a birth defect called hypoplastic left-heart syndrome.
Mrs Ryall said her son would need a heart transplant in 15 to 20 years.
He had "beaten the odds'' by growing and being more active than expected, she said.