function bp_messages_star_message_css_class( $retval = array() ) {
	if ( true === bp_messages_is_message_starred( bp_get_the_thread_message_id() ) ) {
		$status = 'starred';
	} else {
		$status = 'not-starred';
	}

	// Add css class based on star status for the current message.
	$retval[] = "message-{$status}";

	return $retval;
}