diff --git a/src/backend/utils/adt/json.c b/src/backend/utils/adt/json.c
index 19d74014ef5..c52f6732b05 100644
--- a/src/backend/utils/adt/json.c
+++ b/src/backend/utils/adt/json.c
@@ -1948,7 +1948,7 @@ json_object_agg_finalfn(PG_FUNCTION_ARGS)
 	state = PG_ARGISNULL(0) ? NULL : (StringInfo) PG_GETARG_POINTER(0);
 
 	if (state == NULL)
-		PG_RETURN_TEXT_P(cstring_to_text("{}"));
+		PG_RETURN_NULL();
 
 	appendStringInfoString(state, " }");