Put on casual clothes and wig (5,4)
I believe the answer is:
dress down
I believe this clue is a double definition.
'put on casual clothes' is the first definition.
(dress down can mean to dress casually)
'wig' is the second definition.
(I've seen this before)
'and' is the link.
(Other definitions for dress down that I've seen before include "Censure" , "Wear casual clothes (at work)" , "Maybe keep tie off" , "Tear off a strip" , "Adopt casual style (eg, on Fridays)" .)