When they got together
Simpson started dating Cyrus following her split from Hemsworth in August, and her brief fling with Kaitlynn Carter, which ended in September.
Simpson has known her for years and confirmed stories that he'd had a crush on the star since he was a kid and she was a child star.
"I always had an affinity for her," he told The Project in October.
"I've always had a crush on her, I told her that … it worked," he joked.
Not long after they got together, Cyrus said Simpson made her realise that not all men were "evil".
Gushing over her new beau to her millions of Instagram followers, the singer said she "thought she had to be gay" because she thought "all guys were evil" before she struck up a relationship with Simpson, seemingly a thinly veiled attack on Hemsworth's character.
"There are good people out there that just happen to have d**ks. I've only ever met one, and he's on this live,' she said, referring to Simpson.
Miley's sex confession
News of Cyrus and Simpson's split comes after the Hannah Montana star made some X-rated confessions on the Call Her Daddy podcast.
The singer revealed that the first male she had sex with was Liam Hemsworth, whom she married in December 2018.
"I didn't go all the way with a dude until I was 16, but I ended up marrying the guy," Cyrus said on the podcast.
Cyrus also revealed to podcast host Alexandra Cooper that: "The first time I ever hooked up with anyone, it was a girl — two of them, actually".
Cyrus is set to release her new single, Midnight Sky, later today.
Miley's split from Hemsworth
Cyrus and Hemsworth called it quits less than a year after tying the knot.
The singer and the Aussie actor issued a statement confirming that they had separated.
"Liam and Miley have agreed to separate at this time," a spokesman for Cyrus told People magazine last August.
"Ever-evolving, changing as partners and individuals, they have decided this is what's best while they both focus on themselves and careers. They still remain dedicated parents to all of their animals they share while lovingly taking this time apart. Please respect their process and privacy."
The pair had a rocky, on-again, off-again relationship for years since meeting in 2009 on the set of the romantic drama The Last Song.
Cyrus and Hemsworth first became engaged in 2012 but broke up a year later, before reconciling in 2015.
While Cyrus and Hemsworth were committed to each other for years, marriage was never a priority.
But that all changed in December 2018 when they wed during an intimate ceremony at their home in Franklin, Tennessee, after their beloved Malibu home burned down in the California wildfires.
The secret wedding ceremony took place in the pair's lounge room, with Cyrus filmed dancing to Uptown Funk by Mark Ronson in wedding dress by Vivienne Westwood.
