But to anyone who has been paying attention to what Cyrus has said in recent years it should not have come as such a big surprise.
Cyrus has been upfront about her pansexuality and her identification as gender-fluid and as recently as last month made it clear hers was a "complex" marriage and she was not a traditional wife.
When she and Hemsworth broke up after calling off their engagement back in 2013, Cyrus dated both Patrick Schwarzenegger and Stella Maxwell, the Victoria's Secret model ex-girlfriend of Kristen Stewart.
"The reason that people get married sometimes can be old-fashioned, but I think the reason we got married isn't old-fashioned, I actually think it's kind of New Age," Cyrus told Vanity Fair earlier this year about her marriage to Hemsworth.
"We're redefining, to be f***ing frank, what it looks like for someone that's a queer person like myself to be in a hetero relationship."
She added: "A big part of my pride and my identity is being a queer person. What I preach is: People fall in love with people, not gender, not looks, not whatever. What I'm in love with exists on almost a spiritual level. It has nothing to do with sexuality. Like who gives a f**k if he's a guy, if I'm a girl, or if he was a woman, who gives a f**k?"
In an interview with Elle magazine published just weeks before the split was announced, Cyrus said she hated the word "wife" and called her marriage "complex".
"I think it's very confusing to people that I'm married. But my relationship is unique. And I don't know that I would ever publicly allow people in there because it's so complex, and modern, and new that I don't think we're in a place where people would get it," she said.
"I mean, do people really think that I'm at home in a f***ing apron cooking dinner? I'm in a hetero relationship, but I still am very sexually attracted to women.
"People become vegetarian for health reasons, but bacon is still f***ing good, and I know that. I made a partner decision. This is the person I feel has my back the most. I definitely don't fit into a stereotypical wife role. I don't even like that word."
So anyone shocked by the split just haven't been paying attention to anything Cyrus has said.
GROWING UP CYRUS
That Cyrus went into the show business is hardly surprising, given her upbringing. The first child born to her parents Tish and Billy Ray, a popular country singer, her godmother is no less than Dolly Parton. She was born Destiny Hope Cyrus — and singing was her destiny.
She became famous on the Disney Channel series Hannah Montana. Child stars were expected to maintain a squeaky clean image in deference to their young fans and as she got older, Cyrus began to feel hemmed in.
When a 15-year-old Cyrus posed on the cover of Vanity Fair draped in a sheet, people were incensed the Disney Channel star would even hint at the fact that she might be growing up.
"Miley's shame" read the splash on the front page of the New York Post and both Cyrus and Disney apologised.
But a decade later, Cyrus rescinded her apology on social media. "IM NOT SORRY," she wrote on Instagram. "F**k YOU". This kind of unabashed honesty quickly became Cyrus' brand.
GROWING UP MILEY
By the time she was 21, Cyrus was engaged to Hemsworth and, by all accounts, madly in love. She was also producing her own music outside of the Disney Channel remit including her party-pop album Bangerz.
While promoting the album in various performances Cyrus twerked (once, famously, on Robin Thicke at the MTV Video Music Awards) and pole-danced and wore a host of headline-grabbing outfits.
By September 2013, Cyrus and Hemsworth had split but rumours that the pair had reunited kickstarted at Byron Bay's Falls Festival in 2016. Both parties confirmed the relationship in big, splashy magazine stories. "I needed to change so much," Cyrus told Billboard in 2017.
During their two year split Cyrus had changed, or rather, she appeared to grow into herself and her identity. It was during this time, beginning in 2015, that she began to speak openly about her sexuality.
She launched the Happy Hippie Foundation to provide support for homeless youth, in particular homeless LGBTQI adolescents. And Cyrus came out as pansexual.
"I remember telling (my mum) I admire women in a different way," Cyrus told PAPER magazine in 2015.
When she had that conversation with her mother, Cyrus recalls, she was 14. "And she asked me what that meant. And I said 'I love them. I love them like I love boys.' And it was so hard for her to understand … I just asked for her to accept me. And she has."
Cyrus added: "I am literally open to every single thing that is consenting and doesn't involve an animal and everyone is of age. Everything that's legal, I'm down with. Yo, I'm down with any adult — anyone over the age of 18 who is down to love me. I don't relate to being boy or girl, and I don't have my partner relate to boy or girl."
WHAT'S NEXT
If we've learned anything when it comes to the singer it is to take her words at face value.
The statement that Cyrus and Hemsworth put out to People about their relationship clearly said they were "ever-evolving, changing" and that they "have agreed to separate at this time".
The emphasis is our own — we've been down this path before with Cyrus and Hemsworth. They've split, evolved, grown and then found their way back to each other. This is Cyrus' creed: she believes in breaking down the walls of the traditional, conformist box that she has repeatedly been put in.
"I have a new song," Cyrus told ELLE last month. "And the chorus says, 'If you're looking for faithful, that'll never be me. If you're looking for stable, that'll never be me.
"'If you're looking for someone that'll be all that you need, that's never going to be me'."
