Quietly film actor? (6)
I believe the answer is:
player
'actor?' is the definition.
(I know that actor can be written as player)
'quietly film' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'film' becomes 'layer' (film can mean a thin layer of something).
'p'+'layer'='PLAYER'
(Other definitions for player that I've seen before include "South African golfer, Gary" , "Participant in sport or game" , "Important participant" , "Actor - musician" , "Sportsman - instrumentalist" .)