Actors who no longer star, perhaps? (6)
I believe the answer is:
extras
'actors' is the definition.
(extra is a kind of actor)
'no longer star perhaps?' is the wordplay.
'no longer' becomes 'ex'.
'perhaps?' indicates an anagram (I've seen 'perhaps' mean this).
'star' is an anagram of 'tras'.
'ex'+'tras'='EXTRAS'
'who' is the link.
(Other definitions for extras that I've seen before include "Spear-carriers" , "Additional items surplus to requirements, spares" , "Bit actors in film" , "Accessories" , "Wides, byes, etc." .)