diff --git a/indra/llui/lluistring.cpp b/indra/llui/lluistring.cpp
index 561f53c4b..74b1da1b5 100644
--- a/indra/llui/lluistring.cpp
+++ b/indra/llui/lluistring.cpp
@@ -32,6 +32,7 @@
 
 #include "linden_common.h"
 #include "lluistring.h"
+#include "llfasttimer.h"
 #include "llsd.h"
 #include "lltrans.h"