Last week's iTunes singles chart was topped by Taylor Swift's smash [article id="1692958"]"We Are Never Ever Getting Back Together."[/article]
 But the song just below it is a surprise hit that isn't even slated to appear on her upcoming [article id="1693123"]Red[/article]
 album.

It's called "Ronan" and Swift debuted it on Friday during an appearance on the all-star Stand Up To Cancer telethon. The tune is a real-life story told from perspective of three-year-old cancer victim Ronan Thompson's mother, Maya, who heard the touching acoustic song for the first time when it was performed on the show.

"She called me a week before to tell me about the song," Thompson told MTV News. Though she had met Swift at a pair of Phoenix shows she attended in November -- where Swift told her that she'd been reading Thompson's blog -- Maya said that was the last time the two had touched base. "I was very surprised, to say the least. I heard it for the first time the night it was on TV."

Swift told Thompson she'd learned about Ronan on the blog, which Maya set up shortly after her son was diagnosed with neuroblastoma. The site, which features Maya's letters to her son, was an attempt to tell the story of his illness and deal with his May 2011 death, just three days before his fourth birthday. Though she asked for permission to play "Ronan" on the telethon, Swift did not play it for Thompson beforehand.

"I remember your bare feet down the hallway/ I remember your little laugh," the song begins. "Race cars on the kitchen floor/ Plastic dinosaurs, I love you to the moon and back." The chorus features the affecting lyrics, "Come on baby with me/ We're gonna fly away from here/ You were my best four years."

"It's pretty much the words from my blog," Thompson said of the lyrics. "Listening to it was very emotional and I was blown away by how she got it. She got it in a way that most people don't. She took the time to take the intimate parts of things I'd written and put them into the song."

Thompson has a co-writing credit on the song, with her portion of proceeds going to the Ronan Thompson Foundation. A spokesperson for Swift confirmed on Thursday (September 13) that there are not plans to add "Ronan" to Swift's upcoming Red album.

Thompson watched the telethon with her husband, twin sons and some friends and she said it was hard to listen to the her words come out in Swift's voice. "It was very emotional," she said, describing a feeling as experiencing Ronan's life and death all over again. "It's hard to hear, but she did it in such a beautiful way and it touched so many people. She got it right to a T. She really took the time to go through each thing I've written and she got it 100 percent right." Since the telethon, Thompson said she's gotten a flood of emails that range from positive thoughts from 13-year-old girls to words of encouragement from 70-year-old Army veterans.

The two women haven't spoken since telethon, but Thompson said she's still in awe at how a 22-year-old singer without children could tap into her story with such empathy.

"When we met in Phoenix she had tears streaming down her cheeks when she told me how sorry she was that Ronan passed away," Maya said. "She said she'd been reading our story and said she was so inspired by the love I had for Ronan. I had a moment when I thought, 'this girl's too good to be true.' But she's not. What you see is what you get. She's that kind-hearted."

Though Thompson said she's not planning on turning to songwriting full-time, she's considering offers to turn her blog into a book. "I hope it gives them strength and is a reminder of how powerful a love story between a mother and a child can be," she said of her wish for how "Ronan" will impact those who hear it.