diff --git a/bin/kube-diagrams b/bin/kube-diagrams
index 67194d3..beee205 100755
--- a/bin/kube-diagrams
+++ b/bin/kube-diagrams
@@ -870,9 +870,16 @@ def process_resource(resource):
                 label = cluster_config["label"]
                 labels = query_path(resource, "metadata.labels")
                 if isinstance(labels, dict) and label in labels:
-                    cluster = cluster.get_or_create_cluster(
-                                f"{cluster_config['title']}: {labels[label]}"
-                    )
+                    cluster_config_title = cluster_config['title']
+                    if cluster_config_title.find("{") == -1:
+                        metadata_label_value = labels[label]
+                        if metadata_label_value is not None:
+                            cluster_name = f"{cluster_config_title}: {metadata_label_value}"
+                        else:
+                            cluster_name = cluster_config_title
+                    else:
+                        cluster_name = cluster_config_title.format(labels[label])
+                    cluster = cluster.get_or_create_cluster(cluster_name)
                     cluster.graph_attr = cluster_config.get("graph_attr", {})
                     clusters.remove(cluster_config)
                     return process_clusters(cluster, resource, clusters)