diff --git a/charts/kube-prometheus-stack/Chart.yaml b/charts/kube-prometheus-stack/Chart.yaml
index 25e183c61320..f32a1e982a3e 100644
--- a/charts/kube-prometheus-stack/Chart.yaml
+++ b/charts/kube-prometheus-stack/Chart.yaml
@@ -18,7 +18,7 @@ name: kube-prometheus-stack
 sources:
   - https://github.com/prometheus-community/helm-charts
   - https://github.com/prometheus-operator/kube-prometheus
-version: 12.0.2
+version: 12.0.3
 appVersion: 0.43.2
 kubeVersion: ">=1.16.0-0"
 home: https://github.com/prometheus-operator/kube-prometheus
diff --git a/charts/kube-prometheus-stack/templates/prometheus-operator/deployment.yaml b/charts/kube-prometheus-stack/templates/prometheus-operator/deployment.yaml
index 29f2396a9a0c..c1915236992f 100644
--- a/charts/kube-prometheus-stack/templates/prometheus-operator/deployment.yaml
+++ b/charts/kube-prometheus-stack/templates/prometheus-operator/deployment.yaml
@@ -82,8 +82,8 @@ spec:
             {{- if .Values.prometheusOperator.prometheusInstanceNamespaces }}
             - --prometheus-instance-namespaces={{ .Values.prometheusOperator.prometheusInstanceNamespaces | join "," }}
             {{- end }}
-            {{- if .Values.prometheusOperator.thanosInstanceNamespaces }}
-            - --thanos-instance-namespaces={{ .Values.prometheusOperator.thanosInstanceNamespaces | join "," }}
+            {{- if .Values.prometheusOperator.thanosRulerInstanceNamespaces }}
+            - --thanos-ruler-instance-namespaces={{ .Values.prometheusOperator.thanosRulerInstanceNamespaces | join "," }}
             {{- end }}
             {{- if .Values.prometheusOperator.secretFieldSelector }}
             - --secret-field-selector={{ .Values.prometheusOperator.secretFieldSelector }}
diff --git a/charts/kube-prometheus-stack/values.yaml b/charts/kube-prometheus-stack/values.yaml
index 17e5d7d778c7..79803a727219 100644
--- a/charts/kube-prometheus-stack/values.yaml
+++ b/charts/kube-prometheus-stack/values.yaml
@@ -1252,7 +1252,7 @@ prometheusOperator:
   ##
   alertmanagerInstanceNamespaces: []
   prometheusInstanceNamespaces: []
-  thanosInstanceNamespaces: []
+  thanosRulerInstanceNamespaces: []
 
   ## Service account for Alertmanager to use.
   ## ref: https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/