First thing that comes to my mind is Johnny Cash's rendition of "Hurt" by Nine Inch Nails.
Johnny Cash - 'Hurt"An emotional, touching, and powerful performance by Cash. His wife June died only a few months after he released this song, Cash himself died a few months after that.
Trent Reznor, the man who wrote and performed "Hurt" originally, said this about Cash's version:
"I pop the video in, and wow... Tears welling, silence, goose-bumps... Wow. [I felt like] I just lost my girlfriend, because that song isn't mine anymore... It really made me think about how powerful music is as a medium and art form. I wrote some words and music in my bedroom as a way of staying sane, about a bleak and desperate place I was in, totally isolated and alone. [Somehow] that winds up reinterpreted by a music legend from a radically different era/genre and still retains sincerity and meaning — different, but every bit as pure".