function bp_xprofile_fullname_field_id() {
	$id = wp_cache_get( 'fullname_field_id', 'bp_xprofile' );

	if ( false === $id ) {
		global $wpdb;

		$bp = buddypress();
		$id = $wpdb->get_var( $wpdb->prepare( "SELECT id FROM {$bp->profile->table_name_fields} WHERE name = %s", addslashes( bp_xprofile_fullname_field_name() ) ) );

		wp_cache_set( 'fullname_field_id', $id, 'bp_xprofile' );
	}

	return absint( $id );
}