Close friend to regale excitedly (5,3)
I believe the answer is:
alter ego
'close friend' is the definition.
(I've seen this before)
'to regale excitedly' is the wordplay.
'excitedly' indicates an anagram.
'to'+'regale'='toregale'
'toregale' anagrammed gives 'ALTER EGO'.
(Other definitions for alter ego that I've seen before include "Hidden self or very close friend" , "Change conceit for other self" , "A person's secondary personality" , "Other half" , "bosom buddy" .)