diff --git a/src/slic3r/GUI/GCodeViewer.cpp b/src/slic3r/GUI/GCodeViewer.cpp
index 9486b6a10..11f3868f6 100644
--- a/src/slic3r/GUI/GCodeViewer.cpp
+++ b/src/slic3r/GUI/GCodeViewer.cpp
@@ -9,6 +9,8 @@
 #include "libslic3r/LocalesUtils.hpp"
 #include "libslic3r/PresetBundle.hpp"
 
+#include "slic3r/GUI/format.hpp"
+
 #include "GUI_App.hpp"
 #include "MainFrame.hpp"
 #include "Plater.hpp"