Nine Inch Nails frontman Trent Reznor was heartbroken after hearing Johnny Cash's cover of his song Hurt - likening the experience to someone kissing his girlfriend.
The rocker was flattered after the country icon asked to record the track, but insists that listening to Cash's take was an "invasive" experience - because the song is so personal to him.
He says, "(Producer Rick Rubin) called me to ask how I'd feel if Johnny Cash covered Hurt. I said I'd be very flattered but was given no indication it would actually be recorded.
"Two weeks went by. Then I got a CD in the post. I listened to it and it was very strange. It was this other person inhabiting my most personal song. Hearing it was like someone kissing your girlfriend. It felt invasive."
But Reznor has now had a change of heart and considers the 2002 cover version to be one of his proudest accolades.
He adds: "Having Johnny Cash, one of the greatest singer-songwriters of all time, wants to cover your song - that's something that matters to me. It's not so much what other people think, but the honour that this guy felt it was worthy of interpreting.
"He said afterwards it was a song that sounds like one he would have written in the '60s and that's wonderful."