form_dropdown: insert blank?

[eluser]ShawnMA[/eluser]
Using the following code:

Code:

<?php  
            $cities_options = array();
            foreach($cities as $city){
            $cities_options[$city->city_id]=$city->city_full;
            }
            echo "<td>" . form_dropdown('cVenueCity', $cities_options, null, 'id="cVenueCity"') . "</td>";
        ?&gt;

Is it possible to add a beginning value such as -- or "Select City" to the drop down?

Thanks.