diff --git a/lib/compat/wordpress-6.2/get-global-styles-and-settings.php b/lib/compat/wordpress-6.2/get-global-styles-and-settings.php
index 8556a0be1663f..1a81652c29fe0 100644
--- a/lib/compat/wordpress-6.2/get-global-styles-and-settings.php
+++ b/lib/compat/wordpress-6.2/get-global-styles-and-settings.php
@@ -48,6 +48,35 @@ function wp_theme_has_theme_json() {
 	}
 }
 
+if ( ! function_exists( 'wp_theme_get_css_selector_for_block' ) ) {
+	/**
+	 * Lookup a CSS selector for the block provided, and return it if it exists.
+	 *
+	 * @param string $block_name The name of the block to lookup the CSS selector for.
+	 *
+	 * @return string|null the CSS selector for the block.
+	 */
+	function wp_theme_get_css_selector_for_block( $block_name ) {
+		$registry = WP_Block_Type_Registry::get_instance();
+		$blocks   = $registry->get_all_registered();
+
+		if ( isset( $blocks[ $block_name ] ) ) {
+			$block = $blocks[ $block_name ];
+			if (
+				isset( $block->supports['__experimentalSelector'] ) &&
+				is_string( $block->supports['__experimentalSelector'] )
+			) {
+				return $block->supports['__experimentalSelector'];
+			} else {
+				return '.wp-block-' . str_replace( '/', '-', str_replace( 'core/', '', $block_name ) );
+			}
+		}
+
+		// Selector for the block was not found.
+		return null;
+	}
+}
+
 if ( ! function_exists( 'wp_theme_has_theme_json_clean_cache' ) ) {
 	/**
 	 * Function to clean the cache used by wp_theme_has_theme_json method.