Something groovy this way comes

Modesty Blaise (1966)

Former crime boss Modesty Blaise (Monica Vitti) is recruited by British Intelligence to help prevent a diamond theft. Putting her in conflict with Gabriel (Dirk Bogarde), head of the diamond theft ring who maintains a compound on a Mediterranean island. Where his right-hand man, the Amazonian Mrs. Fothergill (Rossella Falk), alleviates her boredom by killing.

Blaise enlists the aid  of her sidekick stroke love interest, expert knife-thrower and master of disguise, Willie Garvin (Terence Stamp).  

Now playing: Marvelettes - Don't Mess With Bill