diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 7f4881b06c..52d5117392 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -3246,7 +3246,7 @@ function wp_timezone_choice($selectedzone) {
 			$selectcontinent = '';
 			if ( !empty($city) ) {
 				$selectcontinent = $continent;
-				$structure .= '<optgroup label="'. esc_attr( translate( $continent ) ) .'">' . "\n"; // continent
+				$structure .= '<optgroup label="'. esc_attr( translate( $continent, "continents-cities" ) ) .'">' . "\n"; // continent
 			}
 		}