Actual heart of famed kingdom (5)
I believe the answer is:
realm
'kingdom' is the definition.
(kingdom is a type of country or realm)
'actual heart of famed' is the wordplay.
'actual' becomes 'real' (similar in meaning).
'heart of' indicates the central letters.
The middle letter of 'famed' is 'm'.
'real'+'m'='REALM'
(Other definitions for realm that I've seen before include "Country" , "Lamer (anag.)" , "where ruler holds sway?" , "Dominion" , "Royal domain" .)