diff --git a/include/internal/catch_console_colour_impl.hpp b/include/internal/catch_console_colour_impl.hpp
index f776952b..315161c5 100644
--- a/include/internal/catch_console_colour_impl.hpp
+++ b/include/internal/catch_console_colour_impl.hpp
@@ -48,6 +48,7 @@ namespace Catch {
 #ifdef __AFXDLL
 #include <AfxWin.h>
 #else
+struct IUnknown;
 #include <windows.h>
 #endif