Support actor in eastern town (8)
I believe the answer is:
grantham
'eastern town' is the definition.
(Lincolnshire town)
'support actor' is the wordplay.
'support' becomes 'grant' (grant is a kind of support).
'actor' becomes 'ham' (ham actor is a kind of actor).
'grant'+'ham'='GRANTHAM'
'in' is the link.
(Other definitions for grantham that I've seen before include "Margaret Thatcher birthplace" , "Lady Thatcher's birthplace" , "English town" , "Lincolnshire town; harm gnat (anag.)" , "Birthplace of Newton and Thatcher" .)