Possible Clues:

• What Zendaya and Shakira use
• What Beyoncé, Bono and Björk each use
• What Beyonce and Madonna use?
• Mark of celebrity uniqueness
• Something Rihanna and Madonna each have
• Feature shared by the women vocalists concealed in 17-, 29-, 45- and 59-Across
• What Madonna and Cher are each known by
• What Rihanna or Prince uses
• What Cher Bono, e.g., goes by
• What Shakira or 25-Down goes by