diff --git a/lcl/interfaces/win32/win32callback.inc b/lcl/interfaces/win32/win32callback.inc
index 2f77ea5e4a..c3d0991b69 100644
--- a/lcl/interfaces/win32/win32callback.inc
+++ b/lcl/interfaces/win32/win32callback.inc
@@ -2728,7 +2728,7 @@ end;
 
  Calls the timerfunction in the Timer Object in the LCL
  ------------------------------------------------------------------------------}
-procedure TimerCallBackProc(window_hwnd : hwnd; msg : DWORD; idEvent: UINT; dwTime: DWORD); stdcall;
+procedure TimerCallBackProc(window_hwnd : hwnd; msg : DWORD; idEvent: UINT_PTR; dwTime: DWORD); stdcall;
 Var
   TimerInfo: PWin32TimerInfo;
   n: Integer;
diff --git a/lcl/interfaces/win32/win32def.pp b/lcl/interfaces/win32/win32def.pp
index 609d4f894a..a5ab2d3cf5 100644
--- a/lcl/interfaces/win32/win32def.pp
+++ b/lcl/interfaces/win32/win32def.pp
@@ -40,7 +40,7 @@ type
   { lazarus win32 Interface definition for additional timer data needed to find the callback}
   PWin32TimerInfo = ^TWin32Timerinfo;
   TWin32TimerInfo = record
-    TimerID: UINT;         // the windows timer ID for this timer
+    TimerID: UINT_PTR;       // the windows timer ID for this timer
     TimerFunc: TWSTimerProc; // owner function to handle timer
   end;
 
diff --git a/lcl/interfaces/win32/win32extra.pas b/lcl/interfaces/win32/win32extra.pas
index d22b63f22b..43b4d384b1 100644
--- a/lcl/interfaces/win32/win32extra.pas
+++ b/lcl/interfaces/win32/win32extra.pas
@@ -410,6 +410,14 @@ const
   SHGFI_LARGEICON = $000000000;
   SHGFI_ICON      = $000000100;
 
+type
+  //64bit safe Timer functions and callback
+  //todo: remove as soon the last supported fpc version has updated header (rev 22526)
+  TIMERPROC = procedure (hWnd: HWND; uMsg: UINT; idEvent: UINT_PTR; dwTime: DWORD); stdcall;
+
+  function SetTimer(hWnd:HWND; nIDEvent:UINT_PTR; uElapse:UINT; lpTimerFunc: TIMERPROC): UINT_PTR; external 'user32' name 'SetTimer';
+  function KillTimer(hWnd:HWND; uIDEvent:UINT_PTR):WINBOOL; external 'user32' name 'KillTimer';
+
 implementation
 
 uses
diff --git a/lcl/interfaces/win32/win32object.inc b/lcl/interfaces/win32/win32object.inc
index 5ce1dcf79b..9c4f2e7225 100644
--- a/lcl/interfaces/win32/win32object.inc
+++ b/lcl/interfaces/win32/win32object.inc
@@ -562,7 +562,7 @@ begin
   if (Interval > 0) and (TimerFunc <> nil) then begin
     New(TimerInfo);
     TimerInfo^.TimerFunc := TimerFunc;
-    TimerInfo^.TimerID := Windows.SetTimer(0, 0, Interval, @TimerCallBackProc);
+    TimerInfo^.TimerID := Win32Extra.SetTimer(0, 0, Interval, @TimerCallBackProc);
     if TimerInfo^.TimerID=0 then
       dispose(TimerInfo)
     else begin
@@ -587,9 +587,9 @@ begin
   while (n>0) do begin
     dec(n);
     TimerInfo := FTimerData[n];
-    if (TimerInfo^.TimerID=UINT(TimerHandle)) then
+    if (TimerInfo^.TimerID=UINT_PTR(TimerHandle)) then
     begin
-      Result := Boolean(Windows.KillTimer(0, UINT(TimerHandle)));
+      Result := Boolean(Win32Extra.KillTimer(0, UINT_PTR(TimerHandle)));
       FTimerData.Delete(n);
       Dispose(TimerInfo);
     end;