diff --git a/Documentation/git-diff-tree.txt b/Documentation/git-diff-tree.txt
index 674ee614c3..9153e4cf2a 100644
--- a/Documentation/git-diff-tree.txt
+++ b/Documentation/git-diff-tree.txt
@@ -95,6 +95,10 @@ separated with a single space are given.
 	hunks disappear, the commit itself and the commit log
 	message is not shown, just like any other "empty diff" cases.
 
+--always::
+	Show the commit itself and the commit log message even
+	if the diff itself is empty.
+
 
 Limiting Output
 ---------------