Brand, possibly unusual for a can, is 'Martyr' (4,2,3)
I believe the answer is:
joan of arc
'martyr' is the definition.
(Joan of Arc was martyred)
'brand possibly unusual for a can' is the wordplay.
'brand possibly' becomes 'Jo' (comedian Jo Brand).
'unusual' indicates anagramming the letters.
'for'+'a'+'can'='foracan'
'foracan' anagrammed gives 'anofarc'.
'jo'+'anofarc'='JOAN OF ARC'
'is' acts as a link.
(Other definitions for joan of arc that I've seen before include "French heroine" , "burning visionary?" , "She was known as the Maid of Orleans" , "national heroine" , "Orleans girl" .)