diff --git a/cernbase.theme b/cernbase.theme
index 463e71450c410bcdb07cb0c63171c913ca73c5f8..34c995da7f3ae1b9321da3dba619b451b6d2bef5 100755
--- a/cernbase.theme
+++ b/cernbase.theme
@@ -36,6 +36,9 @@ function cernbase_preprocess_maintenance_page(&$variables){
  */
 function cernbase_preprocess_html(&$variables) {
   $variables['loading_image'] = '//framework.web.cern.ch/framework/3.0/images/loader.gif';
+
+  // Specific class on body for CERN themes
+  $variables['attributes']['class'][] = 'cern-theme-on';
 }