Jack Sprat wouldn't talk (4,3,3)
I believe the answer is:
chew the fat
I believe this clue is a double definition.
'jack sprat wouldn't' is the first definition.
(reference to the nursery rhyme Jack Sprat)
'talk' is the second definition.
(I've seen this before)
(Other definitions for chew the fat that I've seen before include "Jack Sprat wouldn't" , "Shoot the breeze?" , "Chat casually" , "Argue incessantly" , "as Mrs Sprat was wont to?" .)