diff --git a/admin/classes/form/testoutgoingmailconf_form.php b/admin/classes/form/testoutgoingmailconf_form.php
index f344cfea587..251cdf04335 100644
--- a/admin/classes/form/testoutgoingmailconf_form.php
+++ b/admin/classes/form/testoutgoingmailconf_form.php
@@ -48,6 +48,17 @@ class testoutgoingmailconf_form extends \moodleform {
         $mform->setType('recipient', PARAM_EMAIL);
         $mform->addRule('recipient', get_string('required'), 'required');
 
+        // From user.
+        $options = ['maxlength' => '100', 'size' => '25'];
+        $mform->addElement('text', 'from', get_string('testoutgoingmailconf_fromemail', 'admin'), $options);
+        $mform->setType('from', PARAM_TEXT);
+        $mform->addHelpButton('from', 'testoutgoingmailconf_fromemail', 'admin');
+
+        // Additional subject text.
+        $options = ['size' => '25'];
+        $mform->addElement('text', 'additionalsubject', get_string('testoutgoingmailconf_subjectadditional', 'admin'), $options);
+        $mform->setType('additionalsubject', PARAM_TEXT);
+
         $buttonarray = array();
         $buttonarray[] = $mform->createElement('submit', 'send', get_string('testoutgoingmailconf_sendtest', 'admin'));
         $buttonarray[] = $mform->createElement('cancel');
@@ -56,4 +67,26 @@ class testoutgoingmailconf_form extends \moodleform {
         $mform->closeHeaderBefore('buttonar');
 
     }
+
+    /**
+     * Validate Form field, should be a valid email format or a username that matches with a Moodle user.
+     *
+     * @param array $data
+     * @param array $files
+     * @return array
+     * @throws \dml_exception|\coding_exception
+     */
+    public function validation($data, $files): array {
+        $errors = parent::validation($data, $files);
+
+        if (isset($data['from']) && $data['from']) {
+            $userfrom = \core_user::get_user_by_username($data['from']);
+
+            if (!$userfrom && !validate_email($data['from'])) {
+                $errors['from'] = get_string('testoutgoingmailconf_fromemail_invalid', 'admin');
+            }
+        }
+
+        return $errors;
+    }
 }
diff --git a/admin/testoutgoingmailconf.php b/admin/testoutgoingmailconf.php
index b1f9c58963a..8c2ea92721e 100644
--- a/admin/testoutgoingmailconf.php
+++ b/admin/testoutgoingmailconf.php
@@ -46,9 +46,36 @@ if ($data) {
     $emailuser->email = $data->recipient;
     $emailuser->id = -99;
 
-    $subject = get_string('testoutgoingmailconf_subject', 'admin',
-        format_string($SITE->fullname, true, ['context' => context_system::instance()]));
-    $messagetext = get_string('testoutgoingmailconf_message', 'admin');
+    // Get the user who will send this email (From:).
+    $emailuserfrom = $USER;
+    if ($data->from) {
+        if (!$userfrom = \core_user::get_user_by_email($data->from)) {
+            $userfrom = \core_user::get_user_by_username($data->from);
+        }
+        if (!$userfrom && validate_email($data->from)) {
+            $dummyuser = \core_user::get_user(\core_user::NOREPLY_USER);
+            $dummyuser->id = -1;
+            $dummyuser->email = $data->from;
+            $dummyuser->firstname = $data->from;
+            $emailuserfrom = $dummyuser;
+        } else if ($userfrom) {
+            $emailuserfrom = $userfrom;
+        }
+    }
+
+    // Get the date the email will be sent.
+    $timestamp = userdate(time(), get_string('strftimedatetimeaccurate', 'core_langconfig'));
+
+    // Build the email subject.
+    $subjectparams = new stdClass();
+    $subjectparams->site = format_string($SITE->fullname, true, ['context' => context_system::instance()]);
+    if (isset($data->additionalsubject)) {
+        $subjectparams->additional = format_string($data->additionalsubject);
+    }
+    $subjectparams->time = $timestamp;
+
+    $subject = get_string('testoutgoingmailconf_subject', 'admin', $subjectparams);
+    $messagetext = get_string('testoutgoingmailconf_message', 'admin', $timestamp);
 
     // Manage Moodle debugging options.
     $debuglevel = $CFG->debug;
@@ -60,7 +87,7 @@ if ($data) {
 
     // Send test email.
     ob_start();
-    $success = email_to_user($emailuser, $USER, $subject, $messagetext);
+    $success = email_to_user($emailuser, $emailuserfrom, $subject, $messagetext);
     $smtplog = ob_get_contents();
     ob_end_clean();
 
@@ -76,7 +103,7 @@ if ($data) {
 
     if ($success) {
         $msgparams = new stdClass();
-        $msgparams->fromemail = $USER->email;
+        $msgparams->fromemail = $emailuserfrom->email;
         $msgparams->toemail = $emailuser->email;
         $msg = get_string('testoutgoingmailconf_sentmail', 'admin', $msgparams);
         $notificationtype = 'notifysuccess';
diff --git a/lang/en/admin.php b/lang/en/admin.php
index 7a7f667e7a2..d887a41854d 100644
--- a/lang/en/admin.php
+++ b/lang/en/admin.php
@@ -1354,11 +1354,15 @@ $string['tempdatafoldercleanup'] = 'Clean up temporary data files older than';
 $string['templates'] = 'Templates';
 $string['testoutgoingmailconf'] = 'Test outgoing mail configuration';
 $string['testoutgoingmaildetail'] = 'Note: Before testing, please save your configuration.<br />{$a}';
-$string['testoutgoingmailconf_message'] = 'This is a test message to confirm that you have successfully configured your site\'s outgoing mail.';
 $string['testoutgoingmailconf_errorcommunications'] = 'Your site couldn\'t communicate with your mail server. Please check your outgoing mail configuration.';
+$string['testoutgoingmailconf_message'] = "This is a test message to confirm that you have successfully configured your site's outgoing mail.\n\n Sent:" . '{$a}';
+$string['testoutgoingmailconf_fromemail'] = 'From username or email address';
+$string['testoutgoingmailconf_fromemail_help'] = 'This field emulates sending the message from that user, but the From header used in the real email sent will depend on other settings such as allowedemaildomains';
+$string['testoutgoingmailconf_fromemail_invalid'] = 'Invalid From username or email. Must be a valid email format or an existing username in Moodle.';
 $string['testoutgoingmailconf_sendtest'] = 'Send a test message';
 $string['testoutgoingmailconf_sentmail'] = 'This site has successfully sent a test message to the mail server.<br />From: {$a->fromemail}<br />To: {$a->toemail}';
-$string['testoutgoingmailconf_subject'] = '{$a}: test message';
+$string['testoutgoingmailconf_subject'] = '{$a->site}: test message. {$a->additional} Sent: {$a->time}';
+$string['testoutgoingmailconf_subjectadditional'] = 'Additional subject';
 $string['testoutgoingmailconf_toemail'] = 'To email address';
 $string['themedesignermode'] = 'Theme designer mode';
 $string['themedesignermodewarning'] = 'Theme designer mode is enabled. This should not be enabled on production sites as it can significantly reduce performance.';