SERIESMOVIESNEW & LAST CHANCESCHEDULEFREE EPISODESMoreDocumentariesSpecialsSportsPodcastsHBO MAXSIGN INGET HBOMAXSERIESMOVIESNEW & LAST CHANCESCHEDULEFREE EPISODESMoreDocumentariesSpecialsSportsPodcastsHBO MAXSIGN INGET HBOMAXSIGN INStream all of HBO plus more TV, movies, and Max Originals at no additional cost.SIGN INHBO Max I Know This Much Is True About Season Season 1Thomas Birdsey Played by Mark Ruffalo Dominick’s identical twin brother, Thomas is a diagnosed paranoid schizophrenic, who has been in and out of mental health institutes for his adult life.