FX Networks says today that it will introduce a $5.99 a month service for Comcast’s Xfinity TV subscribers on September 5 enabling them to watch — in home, and on mobile devices — new and old episodes of its original shows, ad-free.

Programming will be available via Xfinity On Demand, the Xfinity Stream app and website, and FXNow. Some series will be available in 4K, and there’ll be opportunities for subscribers to temporarily download current season episodes for viewing when they don’t have an internet connection.

The initiative, called FX+, is similar to AMC Networks’ $4.99 AMC Premiere, launched in June.

But FX says it’s the first ad-supported cable portfolio offering “all seasons of the majority of its original series library.”

FX+ offerings will include American Horror Story, Damages, It’s Always Sunny in Philadelphia, The League, Legion, Louie, Nip/Tuck, Rescue Me, The Shield, Sons of Anarchy, and Terriers.

FX Networks CEO John Landgraf says that his operation has “been diligent about recapturing the in-season stacking rights for all current original programming and recapturing the rights to all seasons of a large portion of our legacy of great original series” which started 15 years ago with The Shield.

As a result, the effort “begins to put us on equal footing with premium networks and streaming services,” he says.

Comcast Cable’s GM of Video and Entertainment Services Matt Strauss says that initiatives such as FX+ “explore what it means to be a network in the future” and “experiment with new ways to super-serve our customers.”