Actress, as Doolittle, affected by that role (9,6)
I believe the answer is:
elizabeth taylor
'actress' is the definition.
(I've seen this before)
'doolittle affected by that role' is the wordplay.
'doolittle' becomes 'eliza' (I've seen this in another clue).
'affected' indicates anagramming the letters.
'by'+'that'+'role'='bythatrole'
'bythatrole' with letters rearranged gives 'bethtaylor'.
'eliza'+'bethtaylor'='ELIZABETH TAYLOR'
'as' acts as a link.
(Other definitions for elizabeth taylor that I've seen before include "Eight times married British-American actress, d. 2011" , "Hollywood actress" .)