diff --git a/django/forms/fields.py b/django/forms/fields.py
index afbf6146b0..b582659099 100644
--- a/django/forms/fields.py
+++ b/django/forms/fields.py
@@ -594,7 +594,18 @@ class NullBooleanField(BooleanField):
     widget = NullBooleanSelect
 
     def clean(self, value):
-        return {True: True, False: False}.get(value, None)
+        """
+        Explicitly checks for the string 'True' and 'False', which is what a
+        hidden field will submit for True and False. Unlike the
+        Booleanfield we also need to check for True, because we are not using
+        the bool() function
+        """
+        if value in (True, 'True'):
+            return True
+        elif value in (False, 'False'):
+            return False
+        else:
+            return None
 
 class ChoiceField(Field):
     widget = Select
diff --git a/tests/regressiontests/forms/fields.py b/tests/regressiontests/forms/fields.py
index ab7968f4a4..cbd59a4089 100644
--- a/tests/regressiontests/forms/fields.py
+++ b/tests/regressiontests/forms/fields.py
@@ -1091,6 +1091,20 @@ False
 >>> f.clean('3')
 >>> f.clean('hello')
 
+# Make sure that the internal value is preserved if using HiddenInput (#7753)
+>>> class HiddenNullBooleanForm(Form):
+...     hidden_nullbool1 = NullBooleanField(widget=HiddenInput, initial=True)
+...     hidden_nullbool2 = NullBooleanField(widget=HiddenInput, initial=False)
+>>> f = HiddenNullBooleanForm()
+>>> print f
+<input type="hidden" name="hidden_nullbool1" value="True" id="id_hidden_nullbool1" /><input type="hidden" name="hidden_nullbool2" value="False" id="id_hidden_nullbool2" />
+>>> f = HiddenNullBooleanForm({ 'hidden_nullbool1': 'True', 'hidden_nullbool2': 'False' })
+>>> f.full_clean()
+>>> f.cleaned_data['hidden_nullbool1']
+True
+>>> f.cleaned_data['hidden_nullbool2']
+False
+
 # MultipleChoiceField #########################################################
 
 >>> f = MultipleChoiceField(choices=[('1', 'One'), ('2', 'Two')])