So popular were their roles that by the fall of 1964 , both McCrea and Crane began receiving billing in the opening credits of the program .
This not only provided both Donna and Alex with best friends , but co-conspirators , as well .
So popular were co-conspirators ' roles that by the fall of 1964 , both McCrea and Crane began receiving billing in the opening credits of the program .
This not only provided both Donna and Alex with best friends , but co-conspirators , as well .