Accost ’Arry, protecting fellow actor (2-4)
I believe the answer is:
co-star
'fellow actor' is the definition.
'accost 'arry protecting' is the wordplay.
'protecting' says the answer is hidden in the clue.
'CO-STAR' is hidden in the letters of 'accost arry'.
(Other definitions for co-star that I've seen before include "share top billing" , "Joint equal performer" , "Performer meriting joint billing" , "Joint main actor" , "One of joint leads" .)