Related Clues:

• Did karaoke
• Wooed with a melody
• Crooned a tune
• Provided backup, say
• Interpreted numbers
• Took a turn at the karaoke bar
• Performed at the Met
• Did vocals
• Snitched on one's cohorts
• Competed on "The Voice"
• Told the cops everything
• Entertained with a tune
• Ratted out the bad guys
• Delivered some notes?
• Performed a tune