Currently in Season 2, 'The Big C' tells the story of Cathy Jamison (Linney) a Midwestern mom, wife and teacher dealing with terminal cancer.
The show averages less than a million viewers in its Mondays at 10PM timeslot. Season 3 will consist of 10 episodes and debut during the second quarter of 2012.
Linney, who won a Golden Globe for her work on the comedy and is up for an Emmy this year, appears opposite Oliver Platt, Gabourey Sidibe and John Benjamin Hickey in 'The Big C.'
Season 2 has featured many guest stars including Cynthia Nixon, Parker Posey, Hugh Dancy and Alan Alda.
Showtime recently handed out a new season orders to 'Nurse Jackie,' 'Gigolos' and 'The Borgias,' but canceled 'United States of Tara.'