Barbie star Margot Robbie almost landed a starring role in American Horror Story.

Since its premiere in 2011, Ryan Murphy and Brad Falchuk’s hit anthology series has ruled the entertainment sphere with its unique set of horror stories, dynamic characters, and hilarious unhinged moments.

However one entry that has remained a favourite among fans is American Horror Story: Asylum, the show’s second season.

The series, which jumps between 1964 and the present day, follows the staff and inmates of the fictional mental institution Briarcliff Manor.

From Sister Jude (Jessica Lange) performing ‘The Name Game’ to Lana Winters (Sarah Paulson) shouting her famous phrase, “Help, the killer is escaping,” Asylum was filled with iconic moments that helped make American Horror Story the pop culture fixture it is today.

However, the season’s main cast almost featured one of Hollywood’s biggest stars.

In a recent interview on the In The Envelope: The Actor’s Podcast, the show’s casting director, Eric Dawson, revealed that Birds of Prey star Robbie auditioned for Asylum.

“Margot has a lot of ‘it’ factors. That’s the tough thing for casting directors who aren’t in the room [anymore] with actors,” he explained.

“Margot is probably one of my favourite auditions of all time, and it was right before she broke out. She was such a star. It was crazy, her star appeal when she walked into the room.”

Dawson then admitted that Robbie failed to land the role because she was out of the show’s “realm of possibility of hiring.”

“Even though she didn’t get that role, that was one of those things as a casting director where you go: ‘This is a star, what do we do with her?'” he said.

“But that’s really the fun part of casting, is seeing the people whose careers are just rising.”

While Robbie didn’t land the part in Asylum, the American Horror Story franchise has gone on to feature an array of superstar talent, including Matt Bomer, Angela Bassett and Kathy Bates.

The upcoming 12th season of AHS, subtitled Delicate, will also include some big Hollywood names.

Based on Danielle Valentine’s upcoming novel Delicate Condition, the story follows Anna Alcott, an actress who longs for a family. After deciding to go through the IVF process to get pregnant, strange and unusual things begin to occur that threaten her dreams of becoming a mother.

Kim Kardashian, Cara Delevingne, Zachary Quinto, Michaela Jaé Rodriguez, Matt Czuchry, Annabelle Dexter-Jones, Odessa A’zion, Debra Monk, and Julie Monk are all set to star alongside series veteran Emma Roberts.

According to the trio of glossy posters, which features Roberts, Delevingne and Kardashian, as well as frightening spider imagery, the season will be split into multiple parts.