Make sure the fridge is fully stocked with Duff: FXX will air all 25 seasons of “The Simpsons” this summer — that’s 552 episodes in a row — in what will be the longest marathon in TV history.

The marathon of the veteran Fox animated series kicks off August 21 at 9 a.m. (Chicago time) and will wrap up September 1.

Over the course of the 12 days, the relatively new cable network FXX will air 552 episodes of “The Simpsons” (through Season 25) as well as “The Simpsons Movie” (airing after episode 400), in chronological order.

The marathon celebrates FXX’s October roll out of “Simpsons World,” a digital experience that will be offered through the website SimpsonsWorld.com and handheld/connected devices via the FX Networks’ app, FXNOW, the authenticated on-demand video service for FX, FXX and FXM.

The upcoming Simpsons World website will let viewers access every episode in the show's 25 season history. (Photo courtesy FXX)

The upcoming Simpsons World website will let viewers access every episode in the show’s 25 season history. (Photo courtesy FXX)

Authenticated viewers (check if you are one at www.fxnetworks.com/providers) will have on-demand access to every “Simpsons” episode ever via SimpsonsWorld.com, and FXNOW apps for iPhone, iPad, Xbox One, Xbox 360, Android phones and tablets, Smart TVs and other set-tops devices.

Simpsons World is scheduled to roll out starting in October. (Photo courtesy FXX)

Simpsons World is scheduled to roll out starting in October. (Photo courtesy FXX)

“I don’t want to over promise, but I think this website will provide you with affordable healthcare,” joked “Simpsons” executive producer Al Jean at the TV critics’ tour Monday in Beverly Hills.

The digital offerings will have plenty of bells and whistles, including new ways to explore Springfield’s characters and locations, as well as the ability for users to curate personal playlists and share show clips and quotes.

Every Sunday, FXX will broadcast a thematic mini-marathon made up of eight “Simpsons” episodes beginning at 3 p.m. (Chicago time) and leading into the 7 p.m. broadcast on Fox.