Taylor Swift’s “Ronan”

Last night was evidently the first time she’s performed this song in public:

“Ronan” is dedicated to a 4-year-old boy who died last year of neuroblastoma. Swift, 22, wrote the song after reading the blog of Ronan’s mother, Maya Thompson, who is credited as a co-writer.

According to a person familiar with the show, but who asked not to be identified because they were not authorized to speak, the song has never been performed in public. After the telethon, it will be available on iTunes; all proceeds will go to cancer-related charities.

It’s mournful, nostalgic, tender —and devastating.