Strange article about piece of fiction (5)
I believe the answer is:
alien
'strange' is the definition.
('alien' can be a synonym of 'strange')
'article about piece of fiction' is the wordplay.
'article' becomes 'an' (indefinite article).
'about' indicates putting letters inside.
'piece of fiction' becomes 'lie' (I've seen this before).
'an' enclosing 'lie' is 'ALIEN'.
(Other definitions for alien that I've seen before include "Martian, say" , "Creature from another planet" , "Foreign - film directed by Ridley Scott" , "extraneous" , "Outlandish" .)