Taylor Swift Sings 'Ronan' in Concert & Shares How Cancer Has Affected Her Life: Watch

Taylor Swift 2015
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Taylor Swift performs onstage during The 1989 World Tour Live at MetLife Stadium on July 11, 2015 in East Rutherford, New Jersey. 

Taylor Swift fans in Glendale, Ariz., were in for a special treat at Swift's recent concert.

The singer performed her heartbreaking tune "Ronan," whose lyrics are based on the story of Ronan Thompson, a young boy who died of cancer, which she wrote and recorded in 2012 as part of Stand Up to Cancer. The lyrics come from blog posts written by Thompson's mother, Maya. Outside of the original telecast performance, this marks the first time Swift sang the tune as part of a show -- and she had a very special reason to break out the song: Maya was in the audience.

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"I think that in my opinion, one of the greatest things that a human being can ever do, is to go through something unbearable and then share their experience with the world. And I think, the braver you are, the more completely honest you are," Swift told the audience, per E! Online. "There's a woman here tonight named Maya Thompson…and I wouldn't know half as much as I know about childhood cancer and childhood cancer research if she hadn't shared her story about her son Ronan....The thing about childhood cancer is that it's really really hard to talk about. And it's really not something that you bring up…but the fact that she brought it up, she had this blog called Rockstar Ronan and I would read it every night. And in it was this account of what it was like to watch cancer take over my life. And since then, I've had cancer hit really close to me in my family. So because Maya's right there, I would like you to give her a round of applause, please." 

Thompson was overwhelmed by the gesture. She met Swift backstage and shared on 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."