In a post on her Facebook.com page, she explains she no longer feels comfortable just going through the motions when she sings the tune live.
O'Connor writes, "OK, the time has come for me to cease singing Nothing Compares 2U. The first principle of the manner in which I'm trained as a singer (Bel Canto) is we never sing a song we don't emotionally identify with. After twenty-five years of singing it, nine months or so ago I finally ran out of anything I could use in order to bring some emotion to it.
"I don't want audiences to be disappointed coming along to a show and then not hearing it, so am letting you know here that you won't.
"If I were to sing it just to please people, I wouldn't be doing my job right, because my job is to be emotionally available. I'd be lying. You'd be getting a lie. My job is to give you honesty. I'm trained in honesty. I can't act. It just isn't in my training. I have ceased singing other songs over the years for the same reason."
Sinead enjoyed massive success with the Prince cover in 1990.