DJ can go on Luxembourg (4,4)
I believe the answer is:
john peel
'dj' is the definition.
(I've seen this before)
'can go on luxembourg' is the wordplay.
'can' becomes 'john' (slang for toilet).
'go' becomes 'pee' (both can mean to urinate).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'luxembourg' becomes 'L' (international vehicle registration code).
'john'+'pee'+'l'='JOHN PEEL'
(Other definitions for john peel that I've seen before include "DJ" , "Huntsman of legend" .)