Another Hollywood star is set to move to the small screen for a stint as HBO has just given the go ahead to the limited series 'I Know This Much Is True' starring Mark Ruffalo.

The six-episode series is based on Wally Lamb’s New York Times bestseller of the same name and is described as a family saga that follows the parallel lives of identical twin brothers, both played by Ruffalo, who will also executive produce.

According to HBO’s official description, it's "an epic story of betrayal, sacrifice, and forgiveness set against the backdrop of 20th-century America."

Derek Cianfrance ('The Place Beyond the Pines', 'Blue Valentine') serves as writer and executive producer as well as director, with author Lamb also executive producing.

This will mark 'Avengers' star Ruffalo's first regular TV role since he starred in the short-lived UPN cop drama 'The Beat' back in 2000.