diff --git a/include/wx/msw/timer.h b/include/wx/msw/timer.h
index 1db218cbfc..a728aede17 100644
--- a/include/wx/msw/timer.h
+++ b/include/wx/msw/timer.h
@@ -17,6 +17,8 @@
 #endif
 
 #include "wx/object.h"
+#include <windows.h>
+
 
 class WXDLLEXPORT wxTimer : public wxObject
 {
@@ -43,6 +45,8 @@ public:
 
 private:
     DECLARE_ABSTRACT_CLASS(wxTimer)
+
+	friend UINT WINAPI wxTimerProc(HWND WXUNUSED(hwnd), WORD, int idTimer, DWORD);
 };
 
 // Timer functions (milliseconds)
diff --git a/src/msw/timer.cpp b/src/msw/timer.cpp
index 0896d3648d..99cd51d92a 100644
--- a/src/msw/timer.cpp
+++ b/src/msw/timer.cpp
@@ -41,8 +41,6 @@
 #define _EXPORT _export
 #endif
 
-#include <windows.h>
-
 wxList wxTimerList(wxKEY_INTEGER);
 UINT WINAPI _EXPORT wxTimerProc(HWND hwnd, WORD, int idTimer, DWORD);