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

The trio joins Susan Sarandon

, Victor Garber, Allison Janney and Tammy Blanchard as guest stars for Season 3. The season recently wrapped production in Stamford, Conn., before heading to Puerto Rico to film the season finale.Gummer, the daughter of Meryl Streep, also recurs on The Good Wife and has signed on to the CW pilot First Cut. She and Linklater previously worked together last year on the off-Broadway production of The School for Lies. D'Arcy James currently plays Frank, the husband of Debra Messing's character on Smash, which was renewed for a second season on Thursday.The Big C will return for its third season on Sunday, April 8 at 9:30/8:30c on Showtime.