Who, for example, is ahead of a film star princess in frantic contest? (4,4)
I believe the answer is:
drag race
'frantic contest?' is the definition.
(fast car race)
'who for example is ahead of a film star princess' is the wordplay.
'who for example' becomes 'Dr' (Dr Who from the TV show Doctor Who).
'is ahead of' is a charade indicator (letters next to each other) (some letters go in front of others).
'film star princess' becomes 'Grace' (actress Grace Kelly became Princess of Monaco).
'dr'+'a'+'grace'='DRAG-RACE'
'in' is the link.
(Other definitions for drag race that I've seen before include "Short competition between cars, requiring acceleration" , "In speed test" , "motor event" , "Short car event to test acceleration" , "Contest of car acceleration" .)