The four-time Grammy Award-winning artist also is planning a concert tour to support her forthcoming, as-yet-untitled CD.
A single from the collection, her version of "We Can Work It Out," will be available worldwide Tuesday exclusively at iTunes.
"My passion for this project comes from the magical genius of the greatest songwriters of all time," Flack said in a statement. "Love, inspiration, friendship and my own life's lessons come together when I sing the songs they created. I am honored to be a part of the fabulous legacy of the Beatles."