HBO’s I Know this Much is True to premiere this spring! Posted by Wally Lamb on January 23, 2020 in Blog | 0 comments The six-episode limited series, based on my novel of the same name, is set to run this spring. Via movie magic, Mark Ruffalo plays both Dominick Birdsey and his mentally troubled identical twin, Thomas. At the 2020 Television Critics Association winter press tour, writer/director Derek Cianfrance and star Mark Ruffalo discuss the challenges of filming this series. Dr. Patel (The Good Wife’s Archie Punjabi) counsels Dominick about how to negotiate the challenges of being his afflicted brother’s keeper. Psychiatric social worker Lisa Sheffer (Rosie O’Donnell) updates Dominck about his twin’s condition. Dominick (Mark Ruffalo) and Dessa, the ex-wife he still loves (Kathryn Hahn) meet outside the hospital where Thomas has been admitted after an act of self-mutilation.. Dominick’s mother Connie (Melissa Leo) gives him a suitcase. Inside is a document that holds clues about the family’s past.