Hi, im using

add_filter( 'the_title', 'wpse33385_filter_title', 10, 2 );
function wpse33385_filter_title( $title, $post_id )
{
    if( $new_title = get_post_meta( $post_id, 'custom_field_name', true ) )
    {
        return $new_title;
    }
    return $title;
}

That code, to display a different post title when the custom field value exists.. the code works, but when i add this if statement around it, since i only want the post title to be changed on single post pages, i dont get any errors, but the post title remains the regular post title

if (is_single()) {
add_filter( 'the_title', 'wpse33385_filter_title', 10, 2 );
function wpse33385_filter_title( $title, $post_id )
{
    if( $new_title = get_post_meta( $post_id, 'custom_field_name', true ) )
    {
        return $new_title;
    }
    return $title;
}
}

im trying to get this to work, so i can then try to make it work for WooCommerce Product Single pages, if i could get any insight on that i would appreciate it seeing as how ill likely end up back here for help anyways :(

Thanks!