diff --git a/core/extension/gdextension_interface.h b/core/extension/gdextension_interface.h
index cac76d39bdb..9057e04bf32 100644
--- a/core/extension/gdextension_interface.h
+++ b/core/extension/gdextension_interface.h
@@ -268,7 +268,7 @@ typedef void (*GDExtensionClassReference)(GDExtensionClassInstancePtr p_instance
 typedef void (*GDExtensionClassUnreference)(GDExtensionClassInstancePtr p_instance);
 typedef void (*GDExtensionClassCallVirtual)(GDExtensionClassInstancePtr p_instance, const GDExtensionConstTypePtr *p_args, GDExtensionTypePtr r_ret);
 typedef GDExtensionObjectPtr (*GDExtensionClassCreateInstance)(void *p_class_userdata);
-typedef GDExtensionObjectPtr (*GDExtensionClassCreateInstance2)(void *p_class_userdata, bool p_notify_postinitialize);
+typedef GDExtensionObjectPtr (*GDExtensionClassCreateInstance2)(void *p_class_userdata, GDExtensionBool p_notify_postinitialize);
 typedef void (*GDExtensionClassFreeInstance)(void *p_class_userdata, GDExtensionClassInstancePtr p_instance);
 typedef GDExtensionClassInstancePtr (*GDExtensionClassRecreateInstance)(void *p_class_userdata, GDExtensionObjectPtr p_object);
 typedef GDExtensionClassCallVirtual (*GDExtensionClassGetVirtual)(void *p_class_userdata, GDExtensionConstStringNamePtr p_name);
diff --git a/core/object/class_db.cpp b/core/object/class_db.cpp
index b81130f43e7..a65411629f8 100644
--- a/core/object/class_db.cpp
+++ b/core/object/class_db.cpp
@@ -181,7 +181,7 @@ public:
 		return 0;
 	}
 
-	static GDExtensionObjectPtr placeholder_class_create_instance(void *p_class_userdata, bool p_notify_postinitialize) {
+	static GDExtensionObjectPtr placeholder_class_create_instance(void *p_class_userdata, GDExtensionBool p_notify_postinitialize) {
 		ClassDB::ClassInfo *ti = (ClassDB::ClassInfo *)p_class_userdata;
 
 		// Find the closest native parent, that isn't a runtime class.
@@ -192,7 +192,7 @@ public:
 		ERR_FAIL_NULL_V(native_parent->creation_func, nullptr);
 
 		// Construct a placeholder.
-		Object *obj = native_parent->creation_func(p_notify_postinitialize);
+		Object *obj = native_parent->creation_func(static_cast<bool>(p_notify_postinitialize));
 
 		// ClassDB::set_object_extension_instance() won't be called for placeholders.
 		// We need need to make sure that all the things it would have done (even if