The couple that moves together...
In the clip, the 26-year-old "Wrecking Ball" singer is rocking a black lacy bra and black booty shorts next to the 22-year-old Aussie singer as they mime the lyrics to the song and shake their hips in tandem to the beat.
While the social media-happy duo was up to their online antics, Cyrus' ex, Liam Hemsworth, also made a social media cameo on his own page.
"Fresh and crispy fall in Montréal," Hemsworth captioned a shot of himself smiling in a navy hoodie and looking out at some fall foliage over the city.
Cyrus and Hemsworth called it quits over the summer after seven months of marriage. The former Disney star then moved on with a whirlwind romance with pal Kaitlynn Carter followed by her current relationship with Simpson.
Last tweet, Simpson opened up about his lady love on The Kyle & Jackie O Show on Sydney, Australia's KIIS 1065.
"I'm very, very, very romantic," he confessed on the show, adding that, "She'd talked about how she hadn't had that kind of an experience in a relationship before."
For more from the pair, watch the clip below: