Season 8 of the comedy about the dysfunctional Gallagher family debuted last weekend.
"As challenging as it can be for any show simply to maintain viewers in the current TV landscape, Shameless is adding them in droves," David Nevins, president and chief executive officer of Showtime Networks Inc., said in a statement Wednesday.
"But it's no mystery why. The series' reputation for rich and resonant characters and for deep -- and deeply twisted -- comedy has drawn not only faithful longtime viewers, but a steadily growing audience. And creatively, the season that kicked off this past Sunday is stronger than ever."
"We are so grateful to Showtime for giving us the opportunity to continue making Shameless," added series executive producer and show-runner John Wells.
"It's a labor of love -- and a blast -- for all of us."
Rossum tweeted: "Because of your love we will be making A NINTH season of shameless. And thank you Showtime, John Wells & our writers."
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