The episode is titled "Rachel, Jack and Ashley, Too", presumably a reference to this classic British film, and the official synopsis is typically cryptic.
"A lonely teenager yearns to connect with her favourite pop star," it teases, "whose charmed existence isn’t quite as rosy it appears…"
Cyrus plays that pop star, Ashley, in casting that's almost too perfect given that she made her name playing another fictional pop star, Hannah Montana. But if the episode's trailer is anything to go by, Ashley finds herself in an extremely strange situation that Hannah could never have imagined, one caused by freaky future tech – a classic Black Mirror trope.
During an interview with Radio 1 Newsbeat over the weekend, Cyrus described the episode as "outrageously out there and dark".
"This is the story of females in the music industry," she added. "I understand everyone's gone through this but I do think for females in the industry… it's hard to be taken seriously. People assume that if you're not wearing a body suit and singing pop music, why would anyone want to see you."
She also said that Black Mirror's core creative duo, Charlie Brooker and Annabel Jones, delved "really deep" into her own experiences in the music industry when formulating the episode. But at the same time, Cyrus insisted that Ashley's story isn't her own.
"My family is what's kept me the way that I am and kept me still loving music," she explained.
We're calling it now: this episode sounds like it could be kind of a twisted take on Hannah Montana. Check out the trailer for yourself below.