In magazine we oldies read about Hollywood composer (5)
I believe the answer is:
loewe
'hollywood composer' is the definition.
(Frederick Loewe, 1901-1988)
'in magazine we oldies read about' is the wordplay.
'in' indicates a hidden word.
'about' says the letters should be written backwards.
'eweol' is hidden in the letters of 'magazine we oldies read'.
'eweol' backwards is 'LOEWE'.
(Other definitions for loewe that I've seen before include "Lerner's musical partner" , "4 1 [THANK HEAVENS FOR LITTLE GIRLS] writer" .)