[Answered ]-How to add more than one cast for a movie model in Django?

You work with a ManyToManyField [Django-doc] to represent relations where a movie can have multiple MovieCasts and a MovieCast can belong to multiple Movies.

For example:

class MovieCast(models.Model):
    actor_name = models.CharField(max_length=100)

class Movie(models.Model):
    name = models.CharField(max_length=128)
    cast = models.ManyToManyField(
        MovieCast,
        related_name='movies'
    )

We can then construct for example two movies and two MovieCast objects:

titanic = Movie.objects.create(name='Titanic')
laborday = Movie.objects.create(name='Labor Day')

leonardo = MovieCast.objects.create(actor_name='Leonardo DiCaprio')
kate = MovieCast.objects.create(actor_name='Kate Winslet')

titanic.cast.add(leonardo, kate)
laborday.cast.add(kate)

For more information, see the many-to-many relationships section of the documentation.