diff --git a/holoviews/core/overlay.py b/holoviews/core/overlay.py
index 49b5bbef7c..dbb9c03296 100644
--- a/holoviews/core/overlay.py
+++ b/holoviews/core/overlay.py
@@ -194,7 +194,7 @@ def dynamic_mul(*args, **kwargs):
             return other.clone(shared_data=False, callback=callback,
                                streams=[])
         elif not isinstance(other, ViewableElement):
-            raise NotImplementedError
+            return NotImplemented
         return Overlay([self, other])