$object->{_id};
$object->{_private_property_of_template_called_id_leave_it_be};

# Both could then have an accessor method, respectively
sub get_id () { $_[0]->{_id} }
sub get_id () { $_[0]->{ _private_property_of_template_called_id_leave_it_be
 } }

# And each would be called 
$object->get_id();