Bocelli had not been invited to the wedding and did not know the couple.
He was simply passing the church while on holiday in the Ligurian coastal village of Porto Venere, near the Cinque Terre, on Saturday, when he noticed there was a wedding taking place.
Bocelli then sent his wife to speak with the guardian of the church, Rita Giannasi, to ask if he could sing during the service.
“I asked her who her husband was and why he wanted to sing at a service that he hadn't been invited to,” Giannasi told Il Secolo XIX.
“Then she explained that her husband was Andrea Bocelli and he wanted to sing as a gift to the newlyweds."
Bocelli was allowed to sneak into the service and sat at the back of the church, waiting for the right moment.
Eventually he sat down at the organ and started to play, while belting out the Schubert classic, Ave Maria.
The wedding guests listened to the Bocelli's beautiful rendition in stunned silence. No sooner had he finished, Bocelli left the church and got back to his holiday.