diff --git a/php/Shortcodes.php b/php/Shortcodes.php
index 3fbf5dd..30403a3 100644
--- a/php/Shortcodes.php
+++ b/php/Shortcodes.php
@@ -419,7 +419,7 @@ public static function shortcode_function( $atts, $content = '' ) {
 				$block_alignment = 'alignright';
 				break;
 			case 'center':
-				$block_alignment = 'align_center';
+				$block_alignment = 'aligncenter';
 				break;
 			case 'wide':
 				$block_alignment = 'alignwide';