Catherine who portrayed Moira Rose (5)
I believe the answer is:
ohara
(Other definitions for ohara that I've seen before include "Scarlett ....., heroine of ''Gone with the Wind'' (1'4)" , "film heroine" , "Scarlett ..... is famous heroine of fiction (1'4)" , "See 1 Across" , "Maureen ..., star of 'The Quiet Man' (1'4)" .)