According to Lucy Lawless's homepage, http://www.lucylawlessfanclub.com/, Lawless is likely to appear in ten episodes of the third season of Galactica.
I want you guys to know that, barring earthquakes, tsunamis and hurricanes, I’m likely to be doing a 10-episode stint on Battlestar Galactica later this year. I’m not looking to guest on other people’s shows per se, but, in this instance, the plot twists and character development proved to be irresistible to me. It won’t get in the way of my doing other projects, but we’ll keep you up to date as things go along. -- Lucy
Lawless plays D'Anna Biers, a reporter for the Colonial Fleet and made an appearance in Final Cut. She's due to appear in two future episodes.