Clone and insertAfter only once a time

Clone and insertAfter only once a time

HTML
<p class="field-new">content</p>
<p><a class="add-new" href="#">add new</a></p>
jQuery
$('.field-new').hide();
$('.add-new').click( function() {
$(this).parent().siblings('.field-new').clone().insertAfter('.field-new').show();
return false;
});
Can anyone help please? So one click on ".add-new" to add only one new
field ".field-new". Thanks.