When most children visit Santa at Christmas time they ask for a present, but one four-year-old boy decided to use the moment for a different purpose. Prestyn Barnette asked Santa to pray with him for a sick baby he had never met.

A picture of Prestyn, from West Columbia, South Carolina, praying with Santa has captured the hearts of people from all over the world.

Prestyn's parents had told him about Knox Stine, a two-month-old baby who has been in hospital since November after falling unconscious. The family do not know Knox personally, but they had followed his story after coming across it on Facebook.

"We talk about it, and we pray for him and we've gotten Prestyn to pray for him in his nightly prayers as well," Rebekah Sharpe, Prestyn's aunt, told ABC News.

The photo of Prestyn praying for her son reached Knox's mother, who said that although she didn't know them, she was deeply touched by the boy's actions.

"I don't know how they know of us or heard of us or anything... I showed my husband [the photo], and we both just smiled at each other, like, 'Something amazing is happening.' It was just beautiful," Stine told Today.com

Alongside praying for the miraculous recovery of Knox, Prestyn did ask Santa for a Lionel train set for Christmas. Knox's father bought the four-year-old the gift as a thank you for his prayers.

Although Knox is yet to regain consciousness, Stine shared that the prayers of people like Prestyn – who is also planning on giving the baby a Build-a-Bear toy – give her hope.

"We don't even have words to express how we feel, and how thankful we are," she said. "We have confidence and we have faith that God is going to work a miracle for Knox. He has so many people asking him for that."