Carmen say has everyone in punt (6)
I believe the answer is:
'carmen say' is the definition.
(I know that Carmen is a ballet)
'everyone in punt' is the wordplay.
'everyone' becomes 'all' (all people).
'in' means one lot of letters goes inside another.
'punt' becomes 'bet' (punt can mean a bet).
'all' inserted within 'bet' is 'BALLET'.
'has' is the link.
(Other definitions for ballet that I've seen before include "Type of dance" , "Classical dancing style" , "old madrigal" , "kind of skirt" , "Artistic dance form" .)