U.S. cable network HBO says it has renewed its medieval fantasy series \"Game of Thrones\" for a third season to begin airing next year. The Hollywood Reporter said the small-screen adaptation of George R.R. Martin\'s books has been a ratings hit for the network. \"Series creators David Benioff and D.B. Weiss raised our expectations for the second season -- and then surpassed them,\" the entertainment industry trade newspaper quoted HBO programming president Michael Lombardo as saying Tuesday. \"We are thrilled by all the viewer and media support we\'ve received for the series and can\'t wait to see what Dan and David have in store for next season.\"