Furniture useful to an actor (7)
I believe the answer is:
dresser
This clue is a double definition.
'furniture' is the first definition.
(I know that dresser is a type of furniture)
'useful to an actor' is the second definition.
(staff member who dresses an actor)
(Other definitions for dresser that I've seen before include "Welsh sideboard" , "Person working in one theatre" , "Item of bedroom furniture" , "Open-shelved cupboard for displaying dishes" , "help in the theatre" .)