Shadowy character is centre stage for a change (6,5)
I believe the answer is:
secret agent
'shadowy character' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'centre stage for a change' is the wordplay.
'for a change' indicates anagramming the letters.
'centre'+'stage'='centrestage'
'centrestage' with letters rearranged gives 'SECRET AGENT'.
'is' is the link.
Can you help me to learn more?
(Other definitions for secret agent that I've seen before include "Spy" , "007 - centre stage (anag)" , "Conrad character" .)