The "Malibu" singer took to her Instagram on Wednesday, showing that the couple has reunited since the Australian native spent his 23th birthday overseas in Italy.
Cyrus, whose divorce from Liam Hemsworth has yet to be finalized, filmed herself and Simpson "werking out" in a pilates studio.
Baring her abs in a white sports bra and wearing very short shorts, Cyrus lounges on a full-body machine as Simpson is spotted in the background doing jumping squats.
"We have a different idea of 'werking out,'" Cyrus captioned the Instagram story.
Simpson appeared to be feeling the burn as he was overheard panting in the video. Cyrus, meanwhile, appeared relaxed as she stretched out onto the machine and ran her fingers through her hair.
Two hours later, the pop star posted an even closer shot of herself--this time Simpson was not in the frame, and she appeared topless.
"When baby f--ks up but wants you to listen to his song ....Peep the plugs," she captioned the Instagram Story, which showed her laughing and walking away from Simpson, who was heard in the background.
Cyrus showed love for Simpson earlier this week in celebration of the singer's 23rd birthday.
“Happy birthday to my best friend in the entire world @codysimpson,” she wrote. "I love you and our pirate life!”
On Saturday, she shared a second message along with a video of the two of them getting cozy while wearing face masks.
“Happy birthday to my favorite human to get weird with on the entire earth,” she captioned the snap.
According to People, Miley previously used Instagram to explain to her followers that Simpson would be out of town on his actual birthday, meaning that she had to give him his gift a little bit early. The 27-year-old “Malibu” singer gifted Simpson a vintage doctor’s bag inscribed with the personal title “Prince Neptune,” which is a reference to Simpson’s upcoming book.
Cyrus was forced to dispel rumors that she and Simpson had called it quits in late December.