diff --git a/isisd/isis_tlvs.c b/isisd/isis_tlvs.c
index 478542f7e6e7..950676ca43ac 100644
--- a/isisd/isis_tlvs.c
+++ b/isisd/isis_tlvs.c
@@ -6657,7 +6657,7 @@ static void format_tlvs(struct isis_tlvs *tlvs, struct sbuf *buf, struct json_ob
 
 	if (tlvs->mt_router_info_empty) {
 		if (json)
-			json_object_string_add(json, "mtRouterInfo", "none");
+			json_object_object_add(json, "mtRouterInfo", NULL);
 		else
 			sbuf_push(buf, indent, "MT Router Info: None\n");
 	} else {