Dance leader with a heavenly body (5,4)
I believe the answer is:
bossa nova
'dance' is the definition.
(Brazilian dance)
'leader with a heavenly body' is the wordplay.
'leader' becomes 'boss' (boss is a kind of leader).
'with' means one lot of letters go next to another.
'heavenly body' becomes 'nova' (nova is a kind of heavenly body).
'boss'+'a'+'nova'='BOSSA NOVA'
(Other definitions for bossa nova that I've seen before include "lively dance" , "Brazil's measure" , "Dance from Brazil similar to samba" , "Brazilian music, rhythmically related to the samba" , "steps taken" .)