Fleming, one of the leading stars of the opera stage, is not a jazz neophyte. While studying at the State University of New York at Potsdam, she sang in a jazz trio; in fact, during that period, saxophonist Illinois Jacquet heard her sing and asked her to join his big band. She declined, choosing to pursue her operatic studies. (The two did finally perform together in December 2003, months before Jacquet's death, on WNYC radio in New York.)

Fans of Fleming's operatic recordings may be surprised when they hear the new album, she told the Christian Science Monitor earlier this year.

"I sing it an octave lower than I ever sing, as if I'm whispering in somebody's ear," she said. "A few people I've played it for had no idea it's me."