Only Allow post author and “Premium” Role user to comment

Good news, bad news..

Good news
The logic behind it is really simple. You basically wrap the form inside of a simple if statement.

    if(condition){ 
      /*Your form here*/
    } 
    else {echo '<h4>You need to be a premium account to post comments</h4>';}

Bad News
You’ll need to code in another user role. This can usually be done via a plugin. Most plugins offer documentation on how to check for a user’s user-role.

So if the plugin has a function like

get_user_role();

You’d simply place that as your condition. That would look something like this:

  if(get_user_role() == 'premium'){ 
      /*Your form here*/
    } 
  else {echo '<h4>You need to be a premium account to post comments</h4>';}