Showtime is feeling “Shameless.”

Pay cabler has given a 12-episode order to a darkly comic drama series starring William H. Macy and Emmy Rossum from Warner Bros. TV and John Wells Prods. Macy plays Frank Gallagher, the alcoholic patriarch of a large blue-collar family in Chicago. Rossum co-stars as the eldest daughter, Fiona, who is tasked with raising her five siblings.

“Shameless” is based on the British TV series of the same name. Creator Paul Abbott co-wrote the pilot for the U.S. adaptation with Wells and will serve as an exec producer on the series. The pilot shot late last year was helmed by Mark Mylod (“Entourage,” “United States of Tara”).

Wells will be the showrunner on the series, which is expected to go into production in late summer. There’s no word yet on a target preem date.

Showtime Networks entertainment prexy Robert Greenblatt said “Shameless” is a bit of a departure for Showtime because it is such a large ensemble vehicle. Showtime’s signature skeins have tended to be built around larger-than-life central protagonists (think “Dexter,” “Weeds,” “Californication”).

“It’s as big an ensemble as anything we’ve done before. We’re stretching our wings a bit,” Greenblatt told Daily Variety.

He likened the tone of the series to ” ‘Party of Five’ on acid” because the children are essentially forced to parent themselves (the mother is completely out of the picture). But Macy plays his rough-and-tumble character “with such charisma that you can’t help but feel for him,” Greenblatt added.

Macy’s past TV work includes stints as a semi-regular on the Wells-produced “ER” and ABC’s “SportsNight.”

Jeremy White, Cameron Monaghan, Ethan Cutkosky and Emma Kenney co-star as the Gallagher siblings.

“Shameless” has been a mainstay on the U.K.’s Channel 4 since 2004.