All the News (So Far) About I Know This Much Is True

New casting has been announced for I Know This Much Is True, an upcoming limited drama series. Here’s what to know so far.

What's it about? I Know This Much Is True is a family saga that follows the parallel lives of identical twin brothers in a story of betrayal, sacrifice and forgiveness set against the backdrop of 20th-century America.

Who's in it? Three-time Oscar nominee Mark Ruffalo (HBO's award-winning The Normal Heart) stars as twin brothers Dominick and Thomas Birdsey. Oscar winner Melissa Leo (The Fighter, Treme) will also star as their mother, Concettina Ipolita Tempesta Birdsey. Rosie O'Donnell is playing Lisa Sheffer, a social worker at the Hatch Forensic Institute where Thomas is staying, and Emmy Award-winning The Good Wife album Archie Panjabi will play Thomas' new psychologist Dr. Patel.

Imogen Poots has been cast as Dominick's live-in girlfriend Joy Hanks, and Camping's Juliette Lewis will be Nedra Frank, a self-absorbed grad student Dominick hires. Kathryn Hahn, who's also starring in the upcoming Mrs. Fletcher, will play Dessa Constantine, his ex-wife.

How many episodes will there be? Writer and director Derek Cianfrance (The Place Beyond the Pines, Blue Valentine) is behind six episodes based on the 1998 bestselling novel by author Wally Lamb (I'll Take You There, We Are Water, Wishin' and Hopin').

What's happening behind the scenes? Ruffalo will executive-produce the series, alongside writer and director Derek Cianfrance. Ben Browning, Glen Basner, Wally Lamb, Gregg Fienberg and Anya Epstein are also serving as executive producers. Co-executive producers include Lynette Howell Taylor and Jamie Patricof. The series will be made in partnership with FilmNation Entertainment (The Big Sick, Arrival).

Check back for more updates.