Sia is making her feature directorial debut with her upcoming film "Music" but one of her casting choices is raising eyebrows.

The singer/songwriter-turned-filmmaker cast "Dance Mom" alum Maddie Ziegler as an autistic teen even though the 18-year-old is not autistic in real-life. 

Sia defended her choice in a new interview with Australia’s 10 News First (via Yahoo Entertainment). She said it wouldn't have been possible to cast a person on the autism spectrum because she needed an actor who could perform skilled dance sequences. 

"I also needed a dancer, for [the character’s] imaginary life," Sia said in reference to the young character called Music's dream sequences. "It’s not a documentary."

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The film also features Kate Hudson as Zu, Music's half-sister and guardian, and Leslie Odom Jr. as Ebo, Music’s neighbor and friend. 

Sia, 44, told the outlet she "actually tried working with a beautiful young girl nonverbal on the spectrum" but "she found it unpleasant and stressful. So that’s why I cast Maddie."

The "character is based completely on my neuro-atypical friend. He found it too stressful being nonverbal, and I made this movie with nothing but love for him and his mother," she added. 

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According to the movie's description, Zu (Hudson) is a free spirit estranged from her family who suddenly finds herself the sole guardian of her half-sister, Music (Ziegler), The musical drama explores the tenuous bonds that hold us together and imagines a world where those bonds can be strengthened in times of great challenge: love, trust, and being able to be there for each other is everything.

Dancer Maddie Ziegler (L) and singer/songwriter Sia have worked together before on music videos for 'Chandelier' and 'Elastic Heart.'

Dancer Maddie Ziegler (L) and singer/songwriter Sia have worked together before on music videos for 'Chandelier' and 'Elastic Heart.' (Jeff Vespa/WireImage)

Sia first addressed the backlash on social media in November. 

"I cast thirteen neuroatypical people, three trans folk, and not as f--king prostitutes or drug addicts but s [sic] as doctors, nurses and singers," Sia said. 

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Sia wrote 10 original songs for "Music" and plans on releasing a new album to accompany the film's debut.

"Music" will be released overseas on January 14.