Top performer in performing arts (4)
I believe the answer is:
star
'top performer' is the definition.
(I've seen this before)
'performing arts' is the wordplay.
'performing' is an anagram indicator (the letters move around or 'perform').
'arts' is an anagram of 'STAR'.
'in' is the link.
(Other definitions for star that I've seen before include "Rush" , "Astronomer - dreamer" , "may be a dwarf or a giant" , "Famous person" , "Famous performer" .)