Bit role (4)
I believe this clue is a double definition.
'bit' is the first definition.
(I've seen this in other clues)
'role' is the second definition.
(eg a part or role in a film)
(Other definitions for part that I've seen before include "goodbye" , "Portion, segment" , "Bit - leave" , "Divide; role" , "unemployed actor hopes for" .)
'bit role' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cameo that I've seen before include "relief work" , "Brief role" , "Brooch with an engraving in low relief" , "Small role for a well-known actor" , "Item of jewellery with a portrait - distinguished actor's minor role" .)