They are both singers
Bill DeLoach Bill DeLoach (born June 19, 1951 in Baltimore, Maryland), is a singer, keyboardist, guitarist, composer, vocal arranger, musical director, and music producer, who was a member of The Four Seasons and the musical director for entertainer Danny Gans.
Backing vocalist Backing vocalists are singers who provide vocal harmony with the lead vocalist or other backing vocalists. In some cases, a backing singer may sing alone as a lead-in to the main vocalist's entry or to sing a counter-melody. Backing vocalists are used in a broad range of popular music, traditional music and world music styles.