Not moving in theatres today (2,4)
I believe the answer is:
at rest
'not moving' is the definition.
(I've seen this before)
'in theatres today' is the wordplay.
'in' says the answer is hidden in the clue.
'AT REST' is hidden in the letters of 'theatres today'.
(Other definitions for at rest that I've seen before include "Not moving, free from anxiety" , "In repose" , "calm" , "departed" , "Stationary" .)