diff --git a/Modules/_ctypes/ctypes.h b/Modules/_ctypes/ctypes.h
index 8a1df9aa22b..b4a9b78e2fa 100644
--- a/Modules/_ctypes/ctypes.h
+++ b/Modules/_ctypes/ctypes.h
@@ -34,6 +34,7 @@ union value {
 #ifdef HAVE_LONG_LONG
                 PY_LONG_LONG ll;
 #endif
+                long double D;
 };
 
 /*
@@ -305,6 +306,7 @@ struct tagPyCArgObject {
 #ifdef HAVE_LONG_LONG
         PY_LONG_LONG q;
 #endif
+        long double D;
         double d;
         float f;
         void *p;