diff --git a/specification/ml/post_data/MlPostJobDataResponse.ts b/specification/ml/post_data/MlPostJobDataResponse.ts
index 0f279ef596..50e5f6b0c9 100644
--- a/specification/ml/post_data/MlPostJobDataResponse.ts
+++ b/specification/ml/post_data/MlPostJobDataResponse.ts
@@ -31,7 +31,7 @@ export class Response {
     input_record_count: long
     invalid_date_count: long
     job_id: Id
-    last_data_time?: integer
+    last_data_time?: EpochTime<UnitMillis>
     latest_record_timestamp?: EpochTime<UnitMillis>
     missing_field_count: long
     out_of_order_timestamp_count: long