Bill with long hair is a performer (7)
I believe the answer is:
actress
'performer' is the definition.
(I know that actress is a type of actor)
'bill with long hair' is the wordplay.
'bill' becomes 'ac' (short for account).
'with' says to put letters next to each other.
'long hair' becomes 'tress' (tress can mean a lock of hair).
'ac'+'tress'='ACTRESS'
'is a' is the link.
(Other definitions for actress that I've seen before include "Terry, say" , "Stage performer" , "Female in plays/films" , "Female player" , "Female thespian" .)