diff --git a/jsonnet/kube-prometheus/kube-prometheus.libsonnet b/jsonnet/kube-prometheus/kube-prometheus.libsonnet
index 00067dac..513bba9d 100644
--- a/jsonnet/kube-prometheus/kube-prometheus.libsonnet
+++ b/jsonnet/kube-prometheus/kube-prometheus.libsonnet
@@ -45,6 +45,11 @@ local configMapList = k3.core.v1.configMapList;
         preserveUnknownFields: null,
       }),
     },
+    '0thanosrulerCustomResourceDefinition'+: {
+      spec: std.mergePatch(super.spec, {
+        preserveUnknownFields: null,
+      }),
+    },
   },
   grafana+:: {
     dashboardDefinitions: configMapList.new(super.dashboardDefinitions),
diff --git a/manifests/setup/prometheus-operator-0thanosrulerCustomResourceDefinition.yaml b/manifests/setup/prometheus-operator-0thanosrulerCustomResourceDefinition.yaml
index e93d4310..7d66f73b 100644
--- a/manifests/setup/prometheus-operator-0thanosrulerCustomResourceDefinition.yaml
+++ b/manifests/setup/prometheus-operator-0thanosrulerCustomResourceDefinition.yaml
@@ -12,7 +12,6 @@ spec:
     listKind: ThanosRulerList
     plural: thanosrulers
     singular: thanosruler
-  preserveUnknownFields: false
   scope: Namespaced
   validation:
     openAPIV3Schema: