The Hellboy star has been cast alongside Shawnee Smith, who will play the ex-wife of Sheen's counsellor character.
Blair was always a favourite for the role - Sheen recently told U.S. news show Access Hollywood Live, "She's a very special lady and I think as pretty as the day is long and she has never really had the opportunity to do something where she can really shine. Off camera she's hilarious."
