Actor ____ Allen (3)
I believe the answer is:
'actor allen' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tim that I've seen before include "Sir -- Rice, lyricist" , "Tiny Dickens boy from 'A Christmas Carol'" , "-- Brooke-Taylor, comedian; -- Minchin, comedian" , "-- Brooke-Taylor, comic" , "Little fellow" .)