Potential Prince in haze about Queen (4)
I believe the answer is:
frog
'potential prince' is the definition.
(I've seen this in another clue)
'haze about queen' is the wordplay.
'haze' becomes 'fog' (synonyms).
'about' means one lot of letters goes inside another.
'queen' becomes 'r' (abbreviation for regina, e.g. in ER ).
'fog' placed around 'r' is 'FROG'.
'in' is the link.
(Other definitions for frog that I've seen before include "Croaker?" , "Leaping amphibian" , "in grass?" , "Adult tadpole" , "Amphibian - depression in brick" .)