Actor in shambles (3)
I believe the answer is:
ham
'actor' is the definition.
(I know that ham is a type of actor)
'in shambles' is the wordplay.
'in' indicates a hidden word.
'HAM' is hidden in the letters of 'shambles'.
(Other definitions for ham that I've seen before include "This actor overacts" , "Flamboyant actor, meaty type" , "Upper leg meat" , "Poor person acting" , "Meat for actor who overdoes it" .)