Final parts in cast recast for theatrical hit (4)
I believe the answer is:
cats
'theatrical hit' is the definition.
(hit musical)
'final parts in cast recast' is the wordplay.
'cast' anagrams to 'CATS'.
Though, I'm not sure how the anagram is indicated.
'for' is the link.
(Other definitions for cats that I've seen before include "Musical (felines?)" , "Famous feline Lloyd Webber musical" , "Popular musical" , "Domestic pets" , "Musical from TS Eliot" .)