diff --git a/app/vmselect/promql/aggr.go b/app/vmselect/promql/aggr.go
index 2e5e4ebac4..314916c4f6 100644
--- a/app/vmselect/promql/aggr.go
+++ b/app/vmselect/promql/aggr.go
@@ -648,6 +648,9 @@ func aggrFuncOutliersK(afa *aggrFuncArg) ([]*timeseries, error) {
 		})
 
 		// Return only up to k time series with the highest variation.
+		for i := range variations {
+			tss[i] = variations[i].ts
+		}
 		for i, k := range ks {
 			fillNaNsAtIdx(i, k, tss)
 		}
diff --git a/app/vmselect/promql/exec_test.go b/app/vmselect/promql/exec_test.go
index b9c38c3d9b..8ddeff1aa2 100644
--- a/app/vmselect/promql/exec_test.go
+++ b/app/vmselect/promql/exec_test.go
@@ -4221,7 +4221,7 @@ func TestExecSuccess(t *testing.T) {
 	t.Run(`outliersk(1)`, func(t *testing.T) {
 		t.Parallel()
 		q := `outliersk(1, (
-			label_set(1300, "foo", "bar"),
+			label_set(2000, "foo", "bar"),
 			label_set(time(), "baz", "sss"),
 		))`
 		r := netstorage.Result{