Mamie Gummer Mamie Gummer

Off the Map's Mamie Gummer, The New Adventures of Old Christine's Hamish Linklater and Smash's Brian D'Arcy James will guest-star on The Big C this season, Showtime announced Friday.

Gummer and Linklater will play a young couple who could give Cathy (Laura Linney) a shot at joy with an unexpected offer. D'Arcy James will play Tim, who will help Sean (John Benjamin Hickey) get over his past relationship in a most unusual way.

Tammy Blanchard to guest-star on The Big C