diff --git a/keras/layers/core.py b/keras/layers/core.py
index d3074a41eb4..7ab8e9953b0 100644
--- a/keras/layers/core.py
+++ b/keras/layers/core.py
@@ -1376,7 +1376,7 @@ def output_shape(self):
         else:
             output_shape_func = marshal.loads(self._output_shape)
             output_shape_func = types.FunctionType(output_shape_func, globals())
-            shape = output_shape_func(self.previous.output_shape)
+            shape = output_shape_func(self.input_shape)
             if type(shape) not in {list, tuple}:
                 raise Exception('output_shape function must return a tuple')
             return tuple(shape)