The 44-year-old singer, who also underwent radiation treatment, 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.
"The words are just coming back to me now," she said after flubbing some of the lyrics to her song, "Soak Up the Sun." "I knew it last night. I think the radiation went to my brain."
Crow played guitar and smiled, and moved gingerly onstage, reports the Associated Press.
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 at the Murat Theater in Indianapolis.
She is also scheduled to perform at Carnegie Hall on May 19 as part of the Rainforest Foundation Benefit concert.