is_page_template not working

Hi trying this code below to get working, but no look so far.
Idea is simple if page template is page-47.php display <h1>Something</h1> else <h1>This will show on any other page</h1> .

<?php if ( is_page_template( 'page-47.php' ) ): ?>

   <h1>Something</h1>

<?php else: ?>

   <h1>This will show on any other page</h1>

<?php endif ?>

Thank You