Rock band or movie star (6)
I believe the answer is:
brando
'movie star' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see a link between them that I don't see?
'rock band or' is the wordplay.
'rock' indicates an anagram (the solver must 'rock' the letters around).
'band'+'or'='bandor'
'bandor' anagrammed gives 'BRANDO'.
Can you help me to learn more?
(Other definitions for brando that I've seen before include "heart-throb" , "actor in 4 26 21 [A STREETCAR NAMED DESIRE]" , "Actor who died this year" , "Marlon . . . . . ., star of ''On The Waterfront'' (6)" , "SECOND PART OF 13" .)