diff --git a/docs/source/common/lightning_module.rst b/docs/source/common/lightning_module.rst
index e629c8b7fe91c..532691455ed82 100644
--- a/docs/source/common/lightning_module.rst
+++ b/docs/source/common/lightning_module.rst
@@ -1271,6 +1271,12 @@ on_test_epoch_end
 .. automethod:: pytorch_lightning.core.hooks.ModelHooks.on_test_epoch_end
     :noindex:
 
+on_test_start
+~~~~~~~~~~~~~
+
+.. automethod:: pytorch_lightning.core.hooks.ModelHooks.on_test_start
+    :noindex:
+
 on_test_end
 ~~~~~~~~~~~