An officer before journey sees close friend (5,3)
I believe the answer is:
alter ego
'close friend' is the definition.
'an officer before journey' is the wordplay.
'an' becomes 'a'.
'officer' becomes 'lt' (I've seen this in other clues**).
'before' becomes 'ere' (usually literary).
'journey' becomes 'go' (I've seen this in other clues).
'a'+'lt'+'ere'+'go'='ALTER EGO'
'sees' is the link.
(Other definitions for alter ego that I've seen before include "bosom buddy" , "One's secondary personality" , "Other self - large toe (anag)" , "Is it Kent" , "Hidden or second self - in Latin" .)