U.S. cable network Showtime said Friday it has ordered two more seasons of its serial killer drama series \"Dexter,\" starring Michael C. Hall. The network says the seventh and eighth seasons of the show will each consist of 12 episodes. Production on the seventh season is to begin next year in Los Angeles. \"\'Dexter\'s\' enormous success is a real tribute to the great achievements of its cast, producers and the powerhouse performance of Michael C. Hall,\" David Nevins, president of entertainment at Showtime, said in a statement. \"The series is bigger than it\'s ever been in its sixth season, both in terms of audience and its impact on the cultural landscape. Together with Michael, the creative team on the show has a very clear sense of where they intend to take the show over the next two seasons and, as a huge fan, I\'m excited to watch the story of Dexter Morgan play out.\"