diff --git a/completion/classes/external.php b/completion/classes/external.php
index 142496be415..b610108d2e4 100644
--- a/completion/classes/external.php
+++ b/completion/classes/external.php
@@ -265,9 +265,11 @@ class core_completion_external extends external_api {
                 $thisprogress  = $userprogress->progress[$activity->id];
                 $state         = $thisprogress->completionstate;
                 $timecompleted = $thisprogress->timemodified;
+                $overrideby    = $thisprogress->overrideby;
             } else {
                 $state = COMPLETION_INCOMPLETE;
                 $timecompleted = 0;
+                $overrideby = null;
             }
 
             $results[] = array(
@@ -276,7 +278,8 @@ class core_completion_external extends external_api {
                        'instance'      => $activity->instance,
                        'state'         => $state,
                        'timecompleted' => $timecompleted,
-                       'tracking'      => $activity->completion
+                       'tracking'      => $activity->completion,
+                       'overrideby'    => $overrideby
             );
         }
 
@@ -308,6 +311,8 @@ class core_completion_external extends external_api {
                             'timecompleted' => new external_value(PARAM_INT, 'timestamp for completed activity'),
                             'tracking'      => new external_value(PARAM_INT, 'type of tracking:
                                                                     0 means none, 1 manual, 2 automatic'),
+                            'overrideby' => new external_value(PARAM_INT, 'The user id who has overriden the status, or null',
+                                VALUE_OPTIONAL),
                         ), 'Activity'
                     ), 'List of activities status'
                 ),
diff --git a/completion/tests/externallib_test.php b/completion/tests/externallib_test.php
index 0a5ec1440e2..355ecc25de4 100644
--- a/completion/tests/externallib_test.php
+++ b/completion/tests/externallib_test.php
@@ -164,7 +164,25 @@ class core_completion_externallib_testcase extends externallib_advanced_testcase
         // We added 4 activities, but only 3 with completion enabled and one of those is hidden.
         $this->assertCount(3, $result['statuses']);
 
-        // Change teacher role capabilities (disable access al goups).
+        // Override status by teacher.
+        $completion->update_state($cmforum, COMPLETION_INCOMPLETE, $student->id, true);
+
+        $result = core_completion_external::get_activities_completion_status($course->id, $student->id);
+        // We need to execute the return values cleaning process to simulate the web service server.
+        $result = external_api::clean_returnvalue(
+            core_completion_external::get_activities_completion_status_returns(), $result);
+
+        // Check forum has been overriden by the teacher.
+        foreach ($result['statuses'] as $status) {
+            if ($status['cmid'] == $forum->cmid) {
+                $this->assertEquals(COMPLETION_INCOMPLETE, $status['state']);
+                $this->assertEquals(COMPLETION_TRACKING_MANUAL, $status['tracking']);
+                $this->assertEquals($teacher->id, $status['overrideby']);
+                break;
+            }
+        }
+
+        // Change teacher role capabilities (disable access all groups).
         $context = context_course::instance($course->id);
         assign_capability('moodle/site:accessallgroups', CAP_PROHIBIT, $teacherrole->id, $context);
         accesslib_clear_all_caches_for_unit_testing();