diff --git a/includes/theme.inc b/includes/theme.inc
index 3868334..341edde 100644
--- a/includes/theme.inc
+++ b/includes/theme.inc
@@ -980,6 +980,13 @@ function theme($hook, $variables = array()) {
       $variables['theme_hook_suggestion'] = $hook;
       $hook = $base_hook;
       $info = $base_hook_info;
+      
+      // Include a file if the base variable processor is held elsewhere.
+      if (!empty($info['includes'])) {
+        foreach ($info['includes'] as $include_file) {
+          include_once DRUPAL_ROOT . '/' . $include_file;
+        }
+      }
     }
   }
   if (isset($info['preprocess functions']) || isset($info['process functions'])) {