diff --git a/mopidy/models.py b/mopidy/models.py
index 0da4a51f..9a22b846 100644
--- a/mopidy/models.py
+++ b/mopidy/models.py
@@ -151,8 +151,6 @@ class ImmutableObject(object):
             super(ImmutableObject, self).__setattr__(key, value)
 
     def __setattr__(self, name, value):
-        if name.startswith('_'):
-            return super(ImmutableObject, self).__setattr__(name, value)
         raise AttributeError('Object is immutable.')
 
     def __delattr__(self, name):