According to People magazine, the star underwent surgery and radiation treatments last February for breast cancer.
Crow, 44, was hired to sing at a sales presentation for My Network TV, a new broadcast network that will use her song "A Change Would Do You Good" as the theme to one of its series.
Sheryl explained, "The words are just coming back to me now. I knew it last night. I think the radiation went to my brain."
The singer, who announced that she’d been diagnosed with breast cancer in February, postponed her March and April 2006 tour dates. She has since rescheduled those shows to begin June 12.