Piece of furniture — one that's helpful to actors (7)
I believe the answer is:
dresser
'piece of furniture' is the definition.
(dresser is a kind of piece of furniture)
'one that's helpful to actors' is the wordplay.
I cannot really see how this works, but
'one' could be 'er' (I've seen this in other clues) and 'er' is found within the answer.
The remaining letters 'dress' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for dresser that I've seen before include "Person who puts clothes" , "One who treats wounds" , "Theatre worker back-stage" , "employed off stage" , "Chest of drawers" .)