diff --git a/lisp/progmodes/c-mode.el b/lisp/progmodes/c-mode.el
index 667f1d174e9..d9c673cd384 100644
--- a/lisp/progmodes/c-mode.el
+++ b/lisp/progmodes/c-mode.el
@@ -1112,6 +1112,10 @@ ENDPOS is encountered."
 			   (if (car indent-stack)
 			       (- (car indent-stack))
 			     opoint))))
+		;; t means we are in a block comment and should
+		;; calculate accordingly.
+		(if (eq val t)
+		    (setq val (calculate-c-indent-within-comment)))
 		(setcar indent-stack
 			(setq this-indent val))))
 	    ;; Adjust line indentation according to its contents