diff --git a/metrics/prometheus.go b/metrics/prometheus.go
index c3044e17..5ced5d30 100644
--- a/metrics/prometheus.go
+++ b/metrics/prometheus.go
@@ -1682,7 +1682,7 @@ func (c *PrometheusCollector) collectContainersInfo(ch chan<- prometheus.Metric)
 					copy(clabels, labels)
 					copy(cvalues, values)
 					for label, value := range metric.Labels {
-						clabels = append(clabels, sanitizeLabelName(label))
+						clabels = append(clabels, sanitizeLabelName("app_"+label))
 						cvalues = append(cvalues, value)
 					}
 					desc := prometheus.NewDesc(metricLabel, "Custom application metric.", clabels, nil)
diff --git a/metrics/testdata/prometheus_metrics b/metrics/testdata/prometheus_metrics
index 1b1e389a..19952b31 100644
--- a/metrics/testdata/prometheus_metrics
+++ b/metrics/testdata/prometheus_metrics
@@ -48,14 +48,14 @@ container_cpu_usage_seconds_total{container_env_foo_env="prod",container_label_f
 container_cpu_user_seconds_total{container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",zone_name="hello"} 6e-09 1395066363000
 # HELP container_custom_app_metric_1 Custom application metric.
 # TYPE container_custom_app_metric_1 gauge
-container_custom_app_metric_1{container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",test_label="1_1",test_label_2="2_1",zone_name="hello"} 1.1
-container_custom_app_metric_1{container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",test_label="1_2",test_label_2="2_2",zone_name="hello"} 1.2
+container_custom_app_metric_1{app_test_label="1_1",app_test_label_2="2_1",container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",zone_name="hello"} 1.1
+container_custom_app_metric_1{app_test_label="1_2",app_test_label_2="2_2",container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",zone_name="hello"} 1.2
 # HELP container_custom_app_metric_2 Custom application metric.
 # TYPE container_custom_app_metric_2 gauge
-container_custom_app_metric_2{container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",test_label="test_value",zone_name="hello"} 2
+container_custom_app_metric_2{app_test_label="test_value",container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",zone_name="hello"} 2
 # HELP container_custom_app_metric_3 Custom application metric.
 # TYPE container_custom_app_metric_3 gauge
-container_custom_app_metric_3{container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",test_label="test_value",zone_name="hello"} 3
+container_custom_app_metric_3{app_test_label="test_value",container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",zone_name="hello"} 3
 # HELP container_file_descriptors Number of open file descriptors for the container.
 # TYPE container_file_descriptors gauge
 container_file_descriptors{container_env_foo_env="prod",container_label_foo_label="bar",id="testcontainer",image="test",name="testcontaineralias",zone_name="hello"} 5 1395066363000