diff --git a/dlls/oleaut32/variant.h b/dlls/oleaut32/variant.h
index e5d9a56aea7..9436cb30fc7 100644
--- a/dlls/oleaut32/variant.h
+++ b/dlls/oleaut32/variant.h
@@ -114,7 +114,7 @@ typedef struct tagVARIANT_NUMBER_CHARS
   WCHAR cCurrencyDigitSeparator;
 } VARIANT_NUMBER_CHARS;
 
-unsigned int get_type_size(ULONG*, VARTYPE);
+unsigned int get_type_size(ULONG*, VARTYPE) DECLSPEC_HIDDEN;
 BOOL VARIANT_GetLocalisedText(LANGID, DWORD, WCHAR *) DECLSPEC_HIDDEN;
 HRESULT VARIANT_ClearInd(VARIANTARG *) DECLSPEC_HIDDEN;
 BOOL get_date_format(LCID, DWORD, const SYSTEMTIME *,