New cast for a show (4)
I believe the answer is:
cats
'a show' is the definition.
(I've seen this before)
'new cast' is the wordplay.
'new' indicates an anagram.
'cast' is an anagram of 'CATS'.
'for' acts as a link.
(Other definitions for cats that I've seen before include "Musical (felines?)" , "Musical; animals" , "Show" , "Feline mammals" , "Carnivores - stage musical" .)