J.O'K never had any backup singer per se. He used vocal groups such as The Delltones and others as well as many menbers oif his later bands provided vocal backup.

His major recordings usually had a choir made up of all those elements. Sometimes up to 10 people.

If it is the group you see on his very early video it is The original Delltones. Noel, Pee Wee, Brian and Warren