“On vocal rest not body,” wrote Cyrus, 26, who wore a black workout outfit as she balanced her body over a Pilates barrel with her feet pressed against the wall and her hands in the air.
The singer and actress recently released her single “Slide Away” in August, which came shortly after her split from husband Liam Hemsworth. Earlier this month, Cyrus was hospitalized for one day as a source close to the singer confirmed to PEOPLE that she underwent surgery for tonsillitis.
Her next studio album, She Is Miley Cyrus, is expected to be released before the end of the year.
While Cyrus seems to be taking a reprieve from her vocals, Simpson released a new song on Friday, titled “Golden Thing,” which is inspired by Cyrus.
“Crystal dream, Cali queen/ Radiant hand, vibrant sand,” the Australian singer, 22, belts out at the start of the intimate, guitar-driven track, affectionately adding, “It’s a golden thing she’s got.”
Seemingly offering insight into their relationship dynamic, Simpson sings of “A thousand thrills, a thousand chills,” before adding, “If we could be heard, for whatever it’s worth/ by the rulers in the sky, they’d cry.”
Throwing her full support behind the track, Cyrus shared a photo of the album artwork — which is a close-up shot of her hair and neck — writing “my heart” alongside a black heart emoji.
The Australian star — who has been by Cyrus’ side as she recovers from tonsillitis — recently revealed that Cyrus encouraged him to release the song.
“She was like, ‘If you don’t put this s— out, I’m putting it out on your behalf for you. I’m getting your Spotify login and doing this s— myself,’” he said of the song, which he wrote while she was still recovering.
“I’m very happy. We are very, very happy,” Simpson added. “We just have a ball, yeah, and that’s the most important part of a relationship, you know?”
Although Cyrus and Simpson’s relationship may be new, the pair were friends for years before romance bloomed.
“It is early, but their friendship is long-standing and deeper than people realize,” Simpson’s manager Matt Zeidman told PEOPLE exclusively in a statement last week. “Though they originally met during their own wilder phases, they’re both sober now and are focused on health, work and spending time together. Seems pretty ideal to me.”
The musicians were first spotted on a breakfast date earlier this month, shortly after Cyrus split from influencer Kaitlynn Carter following her separation from Hemsworth, who was photographed kissing actress Maddison Brown last week.
Since then, Cyrus and Simpson have frequently been documenting their time together in a series of steamy social media snaps
by Eric Todisco