diff --git a/theme/classic/classes/output/icon_system_fontawesome.php b/theme/classic/classes/output/icon_system_fontawesome.php
new file mode 100644
index 00000000000..ae2a43ae4bf
--- /dev/null
+++ b/theme/classic/classes/output/icon_system_fontawesome.php
@@ -0,0 +1,56 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Overridden fontawesome icons.
+ *
+ * @package     theme_classic
+ * @copyright   2019 Moodle
+ * @author      Bas Brands <bas@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+namespace theme_classic\output;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Class overriding some of the Moodle default FontAwesome icons.
+ *
+ * @package    theme_classic
+ * @copyright  2019 Moodle
+ * @author     Bas Brands <bas@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class icon_system_fontawesome extends \core\output\icon_system_fontawesome {
+
+    /**
+     * @var array $map Cached map of moodle icon names to font awesome icon names.
+     */
+    private $map = [];
+
+
+    /**
+     * Change the core icon map
+     * @return Array replaced icons.
+     */
+    public function get_core_icon_map() {
+        $iconmap = parent::get_core_icon_map();
+
+        $iconmap['core:i/navigationitem'] = 'fa-square';
+
+        return $iconmap;
+    }
+}
\ No newline at end of file
diff --git a/theme/classic/config.php b/theme/classic/config.php
index dc6c1b8a5a8..6955eb353a1 100644
--- a/theme/classic/config.php
+++ b/theme/classic/config.php
@@ -156,3 +156,4 @@ $THEME->scss = function($theme) {
     return theme_classic_get_main_scss_content($theme);
 };
 $THEME->usefallback = true;
+$THEME->iconsystem = '\\theme_classic\\output\\icon_system_fontawesome';