Little Skye Savren-McCormick, who was diagnosed with juvenile myelomonocytic leukaemia which meant she had to endure blood transplants on a daily basis, was given just a 10% chance of survival by doctors until Hayden Ryals came into her life.
Hayden, then 26-years-old, had registered as a bone marrow donor while at college in Alabama, and when she was told she was a match for a toddler in the state, she decided to donate anonymously.
Unfortunately following the surgery Skye's family were again devastated to be told that she had developed another form of cancer - post-transplant lymphoproliferative disorder - which can occur after a transplant.
However, Skye has been in remission since receiving chemotherapy and further transplants, and when her donor Hayden got in contact with Skye's family through organisation Be the Match, the pair struck up a close correspondence, becoming pen pals.
When Hayden's boyfriend popped the question, she knew she wanted to ask Skye to be her flower girl if she was well enough, and sent her a card on her third birthday asking her to come along.
The pair met for the first time on Hayden's wedding day, where their families witnessed their emotional meeting at the wedding rehearsal.
"We were in the front, looking around, and she [Ryals] came in and immediately came over to Skye and dropped to her knees," Skye's mother Talia told CNN.
On the day of the wedding, Skye took to the aisle dropping fistfuls of petals for Hayden to make her entrance, and guests 'could barely hold it together' as she captured their hearts.
Photographers on the day Mark and Jeannie Broadway were on hand to capture the special moment for the couple and for he McCormick family, while videographer Joshua Bane captured footage both families will no doubt cherish for a life time.
"There wasn't a dry eye in the room," said Jeannie. "You could even hear sobs from people."
"Anyone could be somebody who saves a life," Skye's mother said. "You don’t have to be a superhero."
"She’s everything to me," Hayden said about the three-year-old. "And this whole journey, I’ve never once seen it as me helping her, because I was honoured to do it, and it was a privilege for me to get to do it."
"In my eyes, she's the one that saved me." said Hayden.