Best Interests cast — who's who in the four-part drama?

Best Interests cast Sharon Horgan and Niamh Moriarty sitting on a bed together with a blue sparkly background.

Sharon Horgan and Michael Sheen lead the Best Interests cast, playing two parents battling to stop doctors from turning off the life-support machine of their disabled 13-year-old daughter. 

Created by Jack Thorne (National Treasure, Help) the powerful four-part series centers on Marnie, who suffers from a rare form of Congenital Muscular Dystrophy, a life-limiting condition that leaves her needing constant care.