diff --git a/service/history/workflow/mutable_state_impl.go b/service/history/workflow/mutable_state_impl.go
index d6db698350a..9401abc77d9 100644
--- a/service/history/workflow/mutable_state_impl.go
+++ b/service/history/workflow/mutable_state_impl.go
@@ -310,6 +310,7 @@ func NewMutableState(
 
 		LastCompletedWorkflowTaskStartedEventId: common.EmptyEventID,
 
+		StartTime:              timestamppb.New(startTime),
 		VersionHistories:       versionhistory.NewVersionHistories(&historyspb.VersionHistory{}),
 		ExecutionStats:         &persistencespb.ExecutionStats{HistorySize: 0},
 		SubStateMachinesByType: make(map[string]*persistencespb.StateMachineMap),