Shakespeare's fairy king (6)
I believe the answer is:
oberon
'shakespeare's fairy king' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for oberon that I've seen before include "King of the fairies, husband of Titania" , "Satellite" , "Borneo (anag)" , "King of the fairies (AMND)" , "MND fairy king" .)