diff --git a/flask_restplus/swagger.py b/flask_restplus/swagger.py
index 51e561e7..971c847e 100644
--- a/flask_restplus/swagger.py
+++ b/flask_restplus/swagger.py
@@ -582,9 +582,9 @@ def register_model(self, model):
         name = model.name if isinstance(model, ModelBase) else model
         if name not in self.api.models:
             raise ValueError('Model {0} not registered'.format(name))
+        specs = self.api.models[name]
         if name in self._registered_models:
             return ref(model)
-        specs = self.api.models[name]
         self._registered_models[name] = specs
         if isinstance(specs, ModelBase):
             for parent in specs.__parents__: