diff --git a/src/wp-includes/class-wp-block-supports.php b/src/wp-includes/class-wp-block-supports.php
index a8e2ecb36b..d6ef909af5 100644
--- a/src/wp-includes/class-wp-block-supports.php
+++ b/src/wp-includes/class-wp-block-supports.php
@@ -94,8 +94,7 @@ class WP_Block_Supports {
 	 * @return string[] Array of HTML attributes.
 	 */
 	public function apply_block_supports() {
-		$block_attributes = self::$block_to_render['attrs'];
-		$block_type       = WP_Block_Type_Registry::get_instance()->get_registered(
+		$block_type = WP_Block_Type_Registry::get_instance()->get_registered(
 			self::$block_to_render['blockName']
 		);
 
@@ -104,6 +103,10 @@ class WP_Block_Supports {
 			return array();
 		}
 
+		$block_attributes = array_key_exists( 'attrs', self::$block_to_render )
+			? self::$block_to_render['attrs']
+			: array();
+
 		$output = array();
 		foreach ( $this->block_supports as $block_support_config ) {
 			if ( ! isset( $block_support_config['apply'] ) ) {