Query posts with custom field value

I have the following query

<ul>
<?php
  $featuredPosts = new WP_Query( array(
  	'post_type' => 'events',
  	'post__in' => array(110)
  ) );
while ($featuredPosts->have_posts()) : $featuredPosts->the_post(); ?>
<li>
<?php the_title() ?>
</li>
<?php endwhile; ?>
</ul>

which works well but what I would like to do is add the “post__in” contents to a custom field on the post and to add those results to the query. I’ve tried

<?php
  $featuredPosts = new WP_Query( array(
  	'post_type' => 'events',
  	'post__in' => array(get_post_meta($post->ID, 'custom_field_name', true))
  ) );
while ($featuredPosts->have_posts()) : $featuredPosts->the_post(); ?>

But this doesn’t return any results.

Any help or ideas would be greatly appreciated.