Cinema legend Welles (5)
I believe the answer is:
'cinema legend welles' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for orson that I've seen before include "- - Welles (actor)" , "-- Welles, director/actor" , "-- Welles, film producer" , "- - Welles (films)" , "_____ Welles, director and star of "Citizen Kane"" .)