Michael Sheen and Sharon Horgan will star in the new BBC drama "Best Interests". The drama was created by BAFTA award-winning screenwriter and disability rights advocate Jack Thorne. The story revolves around a married couple. Alison Oliver and Niamh Moriarty play their two daughters Katie and Marnie respectively. The latter suffers from a life-threatening disease, and the doctor believes that it is in her best interest to die, but her family disagrees. So, a struggle begins. The series is currently being filmed in London and is expected to be broadcast next year.