diff --git a/pkg/cluster/k8sres.go b/pkg/cluster/k8sres.go
index aaa27384a..39b5c16a0 100644
--- a/pkg/cluster/k8sres.go
+++ b/pkg/cluster/k8sres.go
@@ -549,10 +549,6 @@ func (c *Cluster) generateSpiloPodEnvVars(uid types.UID, spiloConfiguration stri
 			Name:  "KUBERNETES_ROLE_LABEL",
 			Value: c.OpConfig.PodRoleLabel,
 		},
-		{
-			Name:  "KUBERNETES_LABELS",
-			Value: labels.Set(c.OpConfig.ClusterLabels).String(),
-		},
 		{
 			Name: "PGPASSWORD_SUPERUSER",
 			ValueFrom: &v1.EnvVarSource{
@@ -588,6 +584,12 @@ func (c *Cluster) generateSpiloPodEnvVars(uid types.UID, spiloConfiguration stri
 			Value: c.OpConfig.PamRoleName,
 		},
 	}
+	// Spilo expects cluster labels as JSON
+	if clusterLabels, err := json.Marshal(labels.Set(c.OpConfig.ClusterLabels)); err != nil {
+		envVars = append(envVars, v1.EnvVar{Name: "KUBERNETES_LABELS", Value: labels.Set(c.OpConfig.ClusterLabels).String()})
+	} else {
+		envVars = append(envVars, v1.EnvVar{Name: "KUBERNETES_LABELS", Value: string(clusterLabels)})
+	}
 	if spiloConfiguration != "" {
 		envVars = append(envVars, v1.EnvVar{Name: "SPILO_CONFIGURATION", Value: spiloConfiguration})
 	}