diff --git a/posthog/temporal/batch_exports/s3_batch_export.py b/posthog/temporal/batch_exports/s3_batch_export.py
index 6a987bd30b27e..bc2b16fd261a2 100644
--- a/posthog/temporal/batch_exports/s3_batch_export.py
+++ b/posthog/temporal/batch_exports/s3_batch_export.py
@@ -526,7 +526,7 @@ def __init__(
     ):
         super().__init__(heartbeater, heartbeat_details, data_interval_start, writer_format)
         self.heartbeat_details: S3HeartbeatDetails = heartbeat_details
-        self.s3_upload = s3_upload
+        self.s3_upload: S3MultiPartUpload | None = s3_upload
         self.s3_inputs = s3_inputs
         self.file_number = 0