diff --git a/helm/mail/templates/statefulset.yaml b/helm/mail/templates/statefulset.yaml
index 14ed96d..a341d88 100644
--- a/helm/mail/templates/statefulset.yaml
+++ b/helm/mail/templates/statefulset.yaml
@@ -88,6 +88,10 @@ spec:
             - secretRef:
                 name: {{ $fullName | quote }}
             {{- end }}
+            {{- if .Values.existingSecret }}
+            - secretRef:
+                name: {{ .Values.existingSecret | quote }}
+            {{- end }}
           {{ with .Values.extraEnv }}env: {{- toYaml . | nindent 12 }}{{ end }}
           volumeMounts:
             - mountPath: /var/spool/postfix
diff --git a/helm/mail/values.yaml b/helm/mail/values.yaml
index 663d921..448453f 100644
--- a/helm/mail/values.yaml
+++ b/helm/mail/values.yaml
@@ -90,6 +90,10 @@ certs:
 #   hello: world
 secret: {}
 
+# Use an existing secret to share with the pod
+# as environment variables.
+existingSecret: ""
+
 # Define a secret which should be deployed together with the
 # chart amd mounted into a specific directory in the pod.
 mountSecret:
@@ -172,4 +176,4 @@ startupProbe:
         ps axf | fgrep -v grep | fgrep -q 'opendkim.sh'
 
 lifecycle:
-  postStart: {}
\ No newline at end of file
+  postStart: {}