Jester to reach princess that's not all there (8)
I believe the answer is:
comedian
'jester' is the definition.
(I've seen this in another clue)
'reach princess that's not all there' is the wordplay.
'reach' becomes 'come' (I've seen this in other clues).
'princess' becomes 'diana' (I have seen 'British princess' mean 'diana' so perhaps 'princess' could also mean 'diana').
'that's not all there' means to remove the last letter.
'diana' with its last letter taken off is 'dian'.
'come'+'dian'='COMEDIAN'
'to' acts as a link.
(Other definitions for comedian that I've seen before include "Hope, say" , "performer" , "Cracker?" , "Funny entertainer" , "Demoniac kind of funny man" .)