Django: Return 'None' from OneToOneField if related object doesn't exist?

I've got a Django class like this:

class Breakfast(m.Model):
    # egg = m.OneToOneField(Egg)
    ...

class Egg(m.Model):
    breakfast = m.OneToOneField(Breakfast, related_name="egg")

Is it possible to have breakfast.egg == None if there is no Egg related to the Breakfast?

Edit: Forgot to mention: I'd rather not change the related_name to something like related_name="_egg", then have something like:

@property
def egg(self):
    try:
        return self.egg
    except ...:
        return None

Because I use the name egg in queries, and I'd rather not have to change the queries to using _egg.