Dermot Mulroney will guest star in Season 5 of Showtime‘s series Shameless in a season-long story arc. Mulroney will play ex-bad boy and recovering addict Sean Pierce, Fiona’s (Emmy Rossum) new manager at Patsy’s Pies. Mulroney most recently appeared with Meryl Streep and Julia Roberts in John Wells’ adaptation of Tracy Letts’ award-winning August: Osage County. He also starred as a series regular in Crisis. Currently, Mulroney is in production on his first horror genre movie, Insidious 3: Into The Further.

Derrmot MulroneyRecently garnering three Emmy Award nominations,  Shameless is in production on its fifth season to air in 2015. Season 4 found the Gallagher family patriarch Frank (Macy) battling back from the depths of liver failure and older sister Fiona’s downward spiral of her own that led to jail time. Based on the long-running hit UK series, , the U.S. version stars William H. Macy and Emmy Rossum, along with Ethan Cutkosky, Emma Greenwell, Shanola Hampton, Steve Howey, Emma Kenney, Cameron Monaghan, Jeremy Allen White, Noel Fisher and special guest star Joan Cusack.

Shameless  is executive produced by John Wells, Andrew Stearn, Christopher Chulack, Davey Holmes and Nancy Pimental. Shameless is produced by Bonanza Productions in association with John Wells Productions and Warner Bros Television.