Bootstrap 3 glyphicons in add ons

To clarify Bass’ answer, with the current version of Bootstrap 3, all you need to do is:

<div class="input-group input-group-lg">
  <input type="text" class="form-control">
  <span class="input-group-addon"><span class=" glyphicon glyphicon-star"></span></span>
</div>

In other words, just the basic Bootstrap markup as described in the docs.