Hall's music partner

OATES

This singer's last name completes the famous duo known for their smooth harmonies.

This clue refers to John Oates, who formed the famous musical duo Hall & Oates with Daryl Hall. The answer "OATES" is the last name of Hall's longtime music partner, known for hits like "Rich Girl" and "Maneater." The clue plays on the well-known pairing, making it straightforward for fans of their music.