Ray Kelly, 64, sang REM's Everybody Hurts in the programme broadcast on Saturday night. It received the plaudits of judges Simon Cowell, David Walliams, Alesha Dixon and Amanda Holden.
He is parish priest in Oldcastle in Co Meath, where mass goers gave him an enthusiastic reception.
He said: "I knew I could put in a fairly good performance but I was amazed at their (judges) comments.
"I was really blown away by Simon's comments and David, Alesha and Amanda."
The clergyman said he was thrilled.
"I am in awe and humbled by it, I really was not expecting it."
Fr Kelly's parents were musical.
He recalled: "It was all there growing up as kids. We were held up like trophies."
The gifted priest has always watched Britain's Got Talent, saying "it is a great variety show", but thought carefully before giving it a go.
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