Sir __ McKellen (3)
I believe the answer is:
ian
'sir mckellen' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ian that I've seen before include "Scottish man's name" , "Albert Beale's first name in EastEnders" , "The familiar Mr Paisley" , "... Fleming, author of the Bond books" , "Male" .)