The couple were promised a wedding to remember - but they had absolutely no idea that this was about to happen.
Chris and Leah O'Kane were stunned when Father Ray Kelly stepped up to his pulpit to give them an emotional - and personalised - rendition of Hallejujah.
The parish priest of Oldcastle, County Meath, told BBC Radio Ulster's Talkback programme that the couple had no idea what was going to happen.
He said: "Normally local people know I sing at weddings, funerals or when I'm asked, but they didn't know.
"They were having their reception at a hotel about 10 miles away and chose our church."
Check it out:
The video has had over 2.5 million views on YouTube and people definitely seem to be fans of Father Ray Kelly's soulful voice.
And we think that's partly due to the fact that some of the lyrics in the classic song - famous for being the track Alexandra Burke performed on the X-Factor in 2008 - were changed to be more fitting to the wedding.
The priest's version started: "We join together here today, to help two people on their way.
"As Leah and Chris start their new life together.
"And now we've reached their special day, we've come to help them celebrate, to help them know how much we love them too."
Were you moved by Father Ray Kelly's rendition of Hallejujah?