Sublime member of singing group (7)
I believe the answer is:
supreme
This clue is a double definition.
'sublime' is the first definition.
(I know that sublime can be written as supreme)
'member of singing group' is the second definition.
(The Supremes were a singing group)
(Other definitions for supreme that I've seen before include "Greatest, highest in excellence" , "Best of all" , "topmost level" , "God" , "over the top" .)