Now that the lead roles in Paul Thomas Anderson' untitled religious drama have been filled by Philip Seymour Hoffman and Joaquin Phoenix, it looks like the supporting cast is starting to fill out.  As we previously reported, the film centers on the charismatic figure of Lancaster Dodd (Hoffman) who forms his own religion after witnessing the horrors of World War II.  His right hand man is an alcoholic drifter (Phoenix) who eventually begins to question his mentor's beliefs.  Earlier drafts heavily implied that the movie was based on the history of Scientology, but that subtext may have been reduced in more recent versions of the script.Variety reports that Laura Dern (Everything Must Go), Jesse Plemons (Friday Night Lights), and David Warshofsky (There Will Be Blood) have joined the film.  Plemons will play Dodd's son, and Warshofsky will play a detective.  No word yet on who Dern will play, but I like all three of these actors and Anderson has always excelled at putting together a strong cast.  Plemons will next be seen in Peter Berg's Battleship while Warshofsky was recently cast in Steven Spielberg's Lincoln.