Small part arrived with ring (5)
I believe the answer is:
cameo
'small part' is the definition.
(small part in a film)
'arrived with ring' is the wordplay.
'arrived' becomes 'came' (come can mean to appear or arrive).
'with' says to put letters next to each other.
'ring' becomes 'O' (letter resembling a ring).
'came'+'o'='CAMEO'
(Other definitions for cameo that I've seen before include "Carving in low relief" , "Short performance" , "Something small but well executed, say role in play" , "Star's tiny role" , "Carved head on gem - short dramatic role for star" .)