Ahead of American Horror Story season 13, all iconic characters are coming under a roof to stand firm ground against the “ultimate evil”.

Ryan Murphy, the series creator, described the all-star team-up as very much its own Marvel’s Avengers moment.

“So Sarah Paulson is playing six or seven roles. Jessica Lange is playing all four of her iconic characters,” he told Entertainment Tonight.

“Evan Peters is playing five characters, and of course Kathy Bates and Emma Roberts and Billie Lourd. It’s like the Avengers! They all come together to defeat the ultimate evil.”

But despite the excitement attached to the upcoming season, the filmmaker had to battle a persistent rumour dogging the horror anthology series.

That is convincing fans that season 13 is not a sequel to Coven, a third season of American Horror Story, aired in 2013.

The rumour was sparked by the on-set photos and made its way to the internet.

In the snaps, Paulson, Roberts and other cast members were dressed as witches – which fans believed was a clue to season three, which follows young witches in New Orleans.

However, Murphy outrightly denied the speculation, stating, ‘Everybody thinks it’s a “Coven” season, and it’s not. It’s all the seasons.”

Moving away from the rumours, the critically-acclaimed filmmaker revealed a shocker.

That is, initially, a score of original cast members turned down the offer to return for season 13.

To convince them, Murphy unveiled his grand plan, which made them agree.

“I pitched Jessica Lange, and she was like, ‘Oh s***, now I have to do it,’” he recalled of the actress’ remarks.

“It’s all of them in one season, and it’s 13 episodes because it’s called ’13.’ I spent many, many months and many years writing it. I wanted to do ’13’ in a special way.”

American Horror Story season 13 airs Sept. 24 on FX and Hulu.