diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
index c87d903ec57..7a404468478 100644
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@@ -336,10 +336,12 @@ class ModelAdmin(BaseModelAdmin):
             exclude = []
         else:
             exclude = list(self.exclude)
+        # if exclude is an empty list we pass None to be consistant with the
+        # default on modelform_factory
         defaults = {
             "form": self.form,
             "fields": fields,
-            "exclude": exclude + kwargs.get("exclude", []),
+            "exclude": (exclude + kwargs.get("exclude", [])) or None,
             "formfield_callback": curry(self.formfield_for_dbfield, request=request),
         }
         defaults.update(kwargs)
@@ -1138,12 +1140,14 @@ class InlineModelAdmin(BaseModelAdmin):
             exclude = []
         else:
             exclude = list(self.exclude)
+        # if exclude is an empty list we use None, since that's the actual
+        # default
         defaults = {
             "form": self.form,
             "formset": self.formset,
             "fk_name": self.fk_name,
             "fields": fields,
-            "exclude": exclude + kwargs.get("exclude", []),
+            "exclude": (exclude + kwargs.get("exclude", [])) or None,
             "formfield_callback": curry(self.formfield_for_dbfield, request=request),
             "extra": self.extra,
             "max_num": self.max_num,
diff --git a/django/forms/models.py b/django/forms/models.py
index d40a1ee55ea..626e727e3ac 100644
--- a/django/forms/models.py
+++ b/django/forms/models.py
@@ -344,16 +344,34 @@ class ModelForm(BaseModelForm):
 
 def modelform_factory(model, form=ModelForm, fields=None, exclude=None,
                        formfield_callback=lambda f: f.formfield()):
-    # HACK: we should be able to construct a ModelForm without creating
-    # and passing in a temporary inner class
-    class Meta:
-        pass
-    setattr(Meta, 'model', model)
-    setattr(Meta, 'fields', fields)
-    setattr(Meta, 'exclude', exclude)
+    # Create the inner Meta class. FIXME: ideally, we should be able to
+    # construct a ModelForm without creating and passing in a temporary
+    # inner class.
+
+    # Build up a list of attributes that the Meta object will have.
+    attrs = {'model': model}
+    if fields is not None:
+        attrs['fields'] = fields
+    if exclude is not None:
+        attrs['exclude'] = exclude
+
+    # If parent form class already has an inner Meta, the Meta we're
+    # creating needs to inherit from the parent's inner meta.
+    parent = (object,)
+    if hasattr(form, 'Meta'):
+        parent = (form.Meta, object)
+    Meta = type('Meta', parent, attrs)
+
+    # Give this new form class a reasonable name.
     class_name = model.__name__ + 'Form'
-    return ModelFormMetaclass(class_name, (form,), {'Meta': Meta,
-                              'formfield_callback': formfield_callback})
+
+    # Class attributes for the new form class.
+    form_class_attrs = {
+        'Meta': Meta,
+        'formfield_callback': formfield_callback
+    }
+
+    return ModelFormMetaclass(class_name, (form,), form_class_attrs)
 
 
 # ModelFormSets ##############################################################
@@ -617,13 +635,6 @@ def inlineformset_factory(parent_model, model, form=ModelForm,
     # enforce a max_num=1 when the foreign key to the parent model is unique.
     if fk.unique:
         max_num = 1
-    if fields is not None:
-        fields = list(fields)
-        fields.append(fk.name)
-    else:
-        # get all the fields for this model that will be generated.
-        fields = fields_for_model(model, fields, exclude, formfield_callback).keys()
-        fields.append(fk.name)
     kwargs = {
         'form': form,
         'formfield_callback': formfield_callback,
diff --git a/tests/regressiontests/modeladmin/models.py b/tests/regressiontests/modeladmin/models.py
index 3a7d3f031f2..ef05b5a048d 100644
--- a/tests/regressiontests/modeladmin/models.py
+++ b/tests/regressiontests/modeladmin/models.py
@@ -37,7 +37,7 @@ class ValidationTestInlineModel(models.Model):
 
 __test__ = {'API_TESTS': """
 
->>> from django.contrib.admin.options import ModelAdmin, HORIZONTAL, VERTICAL
+>>> from django.contrib.admin.options import ModelAdmin, TabularInline, HORIZONTAL, VERTICAL
 >>> from django.contrib.admin.sites import AdminSite
 
 None of the following tests really depend on the content of the request, so
@@ -262,6 +262,46 @@ blank=True for the model field.  Finally, the widget should have the
 >>> list(cmafa.base_fields['transport'].widget.choices)
 [('', u'None'), (1, 'Plane'), (2, 'Train'), (3, 'Bus')]
 
+>>> class AdminConcertForm(forms.ModelForm):
+...     class Meta:
+...         model = Concert
+...         exclude = ('transport',)
+
+>>> class ConcertAdmin(ModelAdmin):
+...     form = AdminConcertForm
+
+>>> ma = ConcertAdmin(Concert, site)
+>>> ma.get_form(request).base_fields.keys()
+['main_band', 'opening_band', 'day']
+
+>>> class AdminConcertForm(forms.ModelForm):
+...     extra = forms.CharField()
+...     class Meta:
+...         model = Concert
+...         fields = ['extra', 'transport']
+
+>>> class ConcertAdmin(ModelAdmin):
+...     form = AdminConcertForm
+
+>>> ma = ConcertAdmin(Concert, site)
+>>> ma.get_form(request).base_fields.keys()
+['extra', 'transport']
+
+>>> class ConcertInline(TabularInline):
+...     form = AdminConcertForm
+...     model = Concert
+...     fk_name = 'main_band'
+
+>>> class BandAdmin(ModelAdmin):
+...     inlines = [
+...         ConcertInline
+...     ]
+
+>>> ma = BandAdmin(Band, site)
+>>> list(ma.get_formsets(request))[0]().forms[0].fields.keys()
+['extra', 'transport', 'id', 'DELETE', 'main_band']
+
+
 >>> band.delete()
 
 # ModelAdmin Option Validation ################################################