Dame __ Mirren (5)
I believe the answer is:
helen
'dame mirren' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for helen that I've seen before include "Her face launched a thousand ships" , "lady" , "Immortal beauty of Troy" , "Famous classical beauty" , "Beautiful daughter of Zeus and Leda who was abducted by Paris" .)