Musical Mars (5)
I believe the answer is:
bruno
'musical mars' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for bruno that I've seen before include "One of the 22 [FRANKS] who fought" , "Giordano -; Sylvie and -, Carroll" , "Sylvie and -- (Lewis Carroll)" , "Famous boxer" .)