diff --git a/src/GUI/GUI.hpp b/src/GUI/GUI.hpp
index d6e38f3b3..30f913d14 100644
--- a/src/GUI/GUI.hpp
+++ b/src/GUI/GUI.hpp
@@ -49,5 +49,9 @@ private:
 };
 
 
+/// Quick reference to this app with its cast applied.
+#define SLIC3RAPP dynamic_cast<App*>(wxTheApp)
+
+
 }} // namespace Slic3r::GUI
 #endif // GUI_HPP