Heavy metal gets the starring role (4)
I believe the answer is:
lead
This clue is a double definition.
'heavy metal' is the first definition.
(lead is a heavy metal)
'the starring role' is the second definition.
(I've seen this in another clue)
'gets' is the link.
(Other definitions for lead that I've seen before include "Toxic, malleable, metallic element" , "Take the van with heavy metal" , "spearhead" , "Live" , "Church windows include this" .)