The singer, seemingly apropos of nothing, posted her backing for the Pirates of the Caribbean actor on Twitter in a post reading: “Just showing my public support for Johnny Depp.”
She added: “I mean, I'd love him to get clean and stop with the jewelry.”
Sia, best known for tracks “Chandelier” and “Cheap Thrills”, then seemed to reference the tapes played during a court case in February that saw Heard admit she had hit Depp. They were recorded in 2015.
It’s unknown why Sia decided to air her views on the matter.
Heard, 34, has been embroiled in a court battle with Depp with both sides alleging abuse at the hands of the other during their marriage.
She claims that the actor “explicitly threatened” to kill her many times during their relationship.
Heard denied being violent with Depp, who filed a $50m defamation lawsuit against his ex-wife in March 2019, after writing an opinion piece in The Washington Post about domestic abuse.
While Depp isn’t named in the piece, the complaint argues that it makes him identifiable. Depp has denied all allegations of domestic violence.
His complaint against Heard refers to “the op-ed’s clear implication that Mr Depp is a domestic abuser” as ”categorically and demonstrably false”.
The actor is attempting to delay the trial due to a delay in the production of his new film Fantastic Beasts 3 because of the pandemic.