Fans are about to get a double dose of Mark Ruffalo [1] in HBO's upcoming limited series, I Know This Much Is True. The network released its first look at the former Marvel star [2] in dual lead roles as Dominick Birdsey and his mentally ill twin brother Thomas. Based on the book by Wally Lamb, the six-part series from The Place Beyond the Pines' Derek Cianfrance follows Dominick as he's forced to accept guardianship of his brother after he harms himself. Dominick, a house painter in Connecticut, is forced to confront the shadows of his past while caring for the paranoid schizophrenic and finds himself dealing with dark memories that he's suppressed for years.

Ruffalo is joined by a myriad of familiar faces, including Rosie O'Donnell [3], Kathryn Hahn, Juliette Lewis, Melissa Leo, Archie Panjabi, and Imogen Poots. Watch the suspenseful trailer above and get ready to dive into the mystery when I Know This Much Is True debuts on April 27.