I have a model called Movie, which has a ManyToManyField called director to a model called Person, and I'm trying to create a form with ModelChoiceField like so:

class MovieSearchForm(forms.Form):
    producer = forms.ModelChoiceField(label='Produced by',
                                      queryset=movies.models.Person.producer_set,
                                      required=False)

but this seems to be failing to compile (I'm getting a ViewDoesNotExist exception for the view that uses the form, but it goes away if I just replace the queryset with all the person objects), I'm guessing because '.producer_set' is being evaluated too 'early'. How can I get this work?

here are the relevant parts of the movie/person classes:

class Person(models.Model):
    name = models.CharField(max_length=100)

class Movie(models.Model):
    ...
    producer = models.ForeignKey(Person, related_name="producers")
    director = models.ForeignKey(Person, related_name="directors")

What I'm trying to do is get ever Person who is used in the producer field of some Movie.