Here's all the drama explained.
Although Sia's "Music" isn't set to debut until 2021, although it seems the tone of its release has already been decided among viewers who feel the autistic community has been wholly disrespected by her casting decision.
Here is the film's synopsis: Kate "plays Zu, a newly sober drug dealer and self-saboteur who finds herself the sole guardian of her half-sister, Music (Ziegler), a teenager with special needs".
After tweeting out the trailer, however, Sia was criticised for the decision to cast an "able bodied & neurotypical" actor to represent an autistic character, and for the film's seemingly "infantilising" tone.
Many people raised concerns with the casting of a non-disabled actor playing the role of a disabled person. It's incredibly offensive as is the infantalisation of the character.
In some final tweets on the topic, Sia stressed that she was really looking forward to an audience watching and sharing their thoughts on the project.
"I did try. It felt more compassionate to use Maddie".
See more of Sia's exchanges with Twitter users below.
One person said: "Did you do any research or consult the community at all?"
"One person added to a thread of criticism, identifying themselves as an autistic actor who would have gladly acted in the movie" on short notice.
One person said: "Autistic people do not bring their families or carers suffering, in fact it's often caregivers who cause harm to disabled people. autistic people need to be allowed to tell their own stories, not this garbage".
"Incredibly disappointing to see yet another misrepresentation of neurodivergent people". "He found it too stressful being non-verbal, and I made this movie with nothing but love for him and his mother".
According to her, many of her friends have disabilities and they are some of the coolest, most talented, funny, kind and intelligent people she knows.
Some people also have an issue with the idea that the main character uses music as a way to "escape" her autism -- implying the disability is something negative. "Now she's trending and being "cancelled".
The National Autistic Society of the United Kingdom were critical of the casting choice, joining the conversation to say "Sia has got this one wrong ... there are so many talented autistic actors out there". "This stupidity has to stop".