diff --git a/postgres_exporter.go b/postgres_exporter.go
index a976e75f..660ec3d1 100644
--- a/postgres_exporter.go
+++ b/postgres_exporter.go
@@ -837,7 +837,8 @@ func queryNamespaceMapping(ch chan<- prometheus.Metric, db *sql.DB, namespace st
 				ch <- prometheus.MustNewConstMetric(metricMapping.desc, metricMapping.vtype, value, labels...)
 			} else {
 				// Unknown metric. Report as untyped if scan to float64 works, else note an error too.
-				desc := prometheus.NewDesc(fmt.Sprintf("%s_%s", namespace, columnName), fmt.Sprintf("Unknown metric from %s", namespace), nil, nil)
+				metricLabel := fmt.Sprintf("%s_%s", namespace, columnName)
+				desc := prometheus.NewDesc(metricLabel, fmt.Sprintf("Unknown metric from %s", namespace), mapping.labels, nil)
 
 				// Its not an error to fail here, since the values are
 				// unexpected anyway.