Matchbox Twenty and its lead singer once saw her as a Zenlike soul, Morissette told Newsweek for its issue hitting newsstands Monday.
"He kept saying that whenever I wasn't with him, his imagining was that I was levitating somewhere, meditating," the Canadian singer said.
But then, "we had the most debaucherous, entertaining, hysterical time together, so they were the first to say that their perception of me was a little off," she told the magazine. She did not elaborate on the debaucherous details.
Morissette is in the process of releasing her latest album "Flavors of Entanglement" and writing her first book, a compilation of essays, photographs and mood-boosting exercises.
She uses writing as an outlet for her anger, which she said is not directed toward ex-boyfriend Ryan Reynolds. The actor recently became engaged to actress Scarlett Johansson.
"I'm really happy for him," she said.