Although American Horror Story casting director seemed to love Margot Robbie's audition, she still failed to land the role on the anthology horror show. Many top stars have turned down iconic parts and later regretted it. However, some stars have been turned down for roles for certain reasons, even if they would have done a great job.

Related: It Wasn't A Blockbuster, But Margot Robbie Says This Was Her Best Role

American Horror Story first premiered in 2011. An anthology series created by Ryan Murphy and Brad Falchuk, each season is based on a different theme, often bringing back actors from previous seasons. During auditions for the show's second season, Asylum, Margot Robbie auditioned for on of the characters. Although she gave what the casting director has called "one of his favorite auditions," Robbie wasn't cast on the show.

Margot Robbie Could Have Been Cast In 'American Horror Story'

American Horror Story
'American Horror Story' Season promos
Via: The Things

Margot Robbie is one of Hollywood's biggest celebrities. The star has displayed her acting skills in a wide variety of films, including I,Tonya, The Suicide Squad, Babylon, and her break-out role, The Wolf of Wall Street.

Shortly before the star was cast in The Wolf of Wall Street, she had auditioned for the popular horror anthology series, American Horror Story. Robbie auditioned for the second season, Asylum, which is set mainly in the 1960s, and follows characters staying and working in Briarcliff, an insane asylum.

Many have speculated about which role the Terminal actress might have auditioned for, with some thinking it could be Sister Mary Eunice, played by Lily Rabe. Others have pointed the character, Grace Bertrand, a patient within the asylum.

According to Backstage, during an interview on Envelope: The Actor's Podcast, casting director Eric Dawson spoke about Margot Robbie's audition for the horror show, explaining that although Robbie's auditions was one of his "favorites", the decision was made not to hire the star.

Dawson has been working with show creator Ryan Murphy since the late '90s, and the casting director has "cast every season of American Horror Story."

Dawson also provided a tip for anyone thinking of auditioning for a Ryan Murphy show. "What I actually think is nice and [Murphy] does watch for is a little thing - 30 seconds at most - at the beginning [of your self tape]. Say something important about yourself, or the shows he does, or the character you're reading for.

He added, "Just a personal moment, and probably not more than 15, 20, 30 seconds. But I think sometimes that's important, to just see the person for a second."

Although she was turned down for AHS, Margot Robbie stunned in another audition, which ended up being her break-out role. During her audition for the Martin Scorsese film, Robbie surprised everybody (likely Leonardo DiCaprio more than anyone) and silenced an entire room when she slapped DiCaprio across the face during her Wolf of Wall Street audition.

Margot Robbie Gave One Of 'American Horror Story's' Casting Director's "Favorite Auditions"

Margot Robbie Los Angeles Premiere Of `Babylon` in black dress
Margot Robbie photgraphed at an event
Via: Instar

Before Margot Robbie shot to stardom, she had worked as an actress on a few shows, including some in her home country of Australia. She had also auditioned for American Horror Story: Asylum, the second season of the horror anthology series, and those in charge of casting loved her audition.

Casting director Eric Dawson said during his interview, "Margot Robbie has a lot of 'it' factors. That's the tough thing for casting directors who aren't in the room [anymore] with actors. Margot is probably one of my favorite auditions of all time, and it was right before she broke out."

Related: The Truth About The Casting Of 'American Horror Story'

Dawson added, "She was such a star. It was crazy, her star appeal when she walked into the room."

It's interesting to think what might have happened with the star's career had she gotten cast in the part she had auditioned for. Would she have continued working with the series, becoming one of the show's returning actors?

Why Wasn't Margot Robbie Cast In American Horror Story: Asylum?

Star Margot Robbie on the red carpet
Margot Robbie on the red carpet
Via: Instar

Before Margot Robbie became a global superstar, she hoped to make her big break. However, after giving a great audition for American Horror Story: Asylum, she wasn't hired for the role.

Casting director Eric Dawson said, "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? Immediately, though, she was out of our realm of the possibility of hiring.

He added, "But that's the fun part of casting, is seeing the people whose careers are just rising."

The casting director didn't give an explanation for why they ultimately chose not to hire the star, but it appears the show would like to see Robbie appear in a future season.

Although Robbie wasn't a big name when she was cast, it seems those in charge of casting loved her audition and thought she was a star. The only reason she didn't get the part appears to be because those in charge of casting felt she was "out of their realm" due to her star power.

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However, other top stars have been cast or made appearances on the series, including Adam Levine, Kathy Bates, Jessica Lange, Angela Bassett, Lady Gaga, Stevie Nicks and most recently, Kim Karsahian, who was cast for season twelve, American Horror Story: Delicate.

Had the actress landed the role in American Horror Story: Asylum, Robbie likely wouldn't have auditioned for The Wolf of Wall Street. After Robbie's performance in that film, and a few others, Robbie quickly became a top star who could start choosing and producing her own projects.