Formed ranks with one Italian director (7)
I believe the answer is:
fellini
'italian director' is the definition.
(Federico Fellini, 1920-1993)
'formed ranks with one' is the wordplay.
'formed ranks' becomes 'fell in' (I've seen this in another clue).
'with' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'fellin'+'i'='FELLINI'
(Other definitions for fellini that I've seen before include "Federico --, Italian film producer" , "It. film director (La Dolce Vita)" , "Shooting Italian" , "It. director of Satyricon" , "Italian film-maker, d. 1993" .)