Can't remember a song from a movie...for my wedding

Ok so maybe someone can help me with this... I am trying to find a song that was in a movie..only problem is I can't remember the movie name or the song name. All I remember is that it is a Celtic/Irish song played at the wedding reception during the movie - the movie is set in current time though. I remember the camera panning past a women on a stage with dark hair singing this amazing Celtic sounding song and it played during a movie that was about a wedding (I think). I have watched every wedding movie I can think of and I cannot find this song. Any help would be greatly appreciated because I would love for this song to play at my wedding! Thank you!