Talk about new song (5)
I believe the answer is:
chant
'song' is the definition.
(I've seen this before)
'talk about new' is the wordplay.
'talk' becomes 'chat' (I've seen this before).
'about' means one lot of letters goes inside another.
'new' becomes 'n'.
'chat' going around 'n' is 'CHANT'.
(Other definitions for chant that I've seen before include "Repetitive song" , "A monotonous song or rhythmic call" , "Intone (psalm)" , "(Ritual) incantation" , "Incantatory song" .)