Taylor Swift Gets Choked Up, Talks Cancer at Show

— -- Taylor Swift shared a heart-breaking story Monday night during one of her concerts in Arizona, as the inspiration for possibly her most gut-wrenching song "Ronan" was in attendance.

Swift, 25, has been open that "Ronan" was written and based on a blog from Maya Thompson, a local Arizona woman who lost her 4-year-old son to cancer.

In videos posted online, you can see Swift slow things down during the show and say, "One of the bravest things a human being can ever do is to go through something absolutely unbearable and then share their experience with the world. And I think the braver you are, the more brutally honest you are."

Swift noticeably tries to hold back the tears as she announces Thompson is in the building.

"I wouldn't know half as much as I know about childhood cancer ... if she hadn't shared her story about her son Ronan," she continued. Swift explains how she found Thompson's blog, Rockstar Ronan, something "I would read every night."

"In it, there's this account of what it's like to watch cancer take over your life," she said, starting to break down. She then references a personal connection to the disease. "Since then, I've had cancer hit really close to me in my family," she said.

Swift, whose mother Andrea was diagnosed with cancer, revealed the news back in April. The "Bad Blood" superstar also explained why the blog inspired her to record "Ronan."

"I took a lot of the things she said and put them into a song," she added. "I put her as the co-writer, because she is the rightful co-writer. All the proceeds of that song going to the Ronan Thompson Foundation."

"I just wanted to take a moment and try and play this song," she said, strumming her guitar. "I can't promise I'll sing it well or not get really emotional."

It's a song Swift rarely plays. In fact, she said the only other time she played the song was during a cancer benefit, but she played it for Thompson.

Thompson and the Ronan Foundation's Twitter account was full of gratitude for Swift and all the stories written about the song and her son.

Thompson also posted to Instagram, "I still can't believe tonight. I still can't believe you did this. This will forever be one of the most special moments of my life. Thank you @taylorswift for your beautiful heart and for never forgetting my Ro. I love you to the moon and back."