Backup singer for Gladys Knight
I believe the answer is:
pip
'backup singer for gladys knight' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pip that I've seen before include "Palindromic pear seed" , "'Seed, of an apple say (3)'" , "one signals lieutenant" , "Defeat at the last moment - . . . at the post" , "star" .)