Taylor Swift has made it a habit to surprise concert goers with special guests on stage.
Most recently, the artist welcomed Julia Roberts and Joan Baez during a rendition of "Style."
But Swift stopped by Glendale, Arizona on Monday night and offered up a different kind of surprise: She sang the track "Ronan" for only the second time in history, following a performance in 2012 during the Stand Up to Cancer special.
The song is about Ronan Thompson, who died from neuroblastoma in 2011, and it uses lyrics from blog entries penned by Ronan’s mother, Maya.
With Maya in attendance at this Arizona show, Swift felt a responsibility to break the single out once again. Watch and listen now: