Many of the song's lyrics appear to reference the pair's breakup.
In "Slide Away," Cyrus sings, "Move on, we're not 17. I'm not who I used to be. You say that everything changed. You're right, we're grown now."
The 26-year-old singer was 17 when the pair met on the set of the movie "The Last Song" in 2009.
Artwork for the song includes a bottle of alcohol and pills floating in a pool, which mirror the references to both in the lyrics: "I want my house in the hills. Don't want the whisky and pills. I don't give up easily but I don't think I'm down."
Another verse in the new single says, “Once upon a time it was made for us, woke up one day and it turned to dust.” Cyrus continues, “Baby, we were found, but now we’re lost. So it’s time to let it go.”
Fans took to social media to share their support of the dreamy song. One wrote on YouTube, "Why are Mileys best songs the ones released after breaking up / about exes" while another on Twitter added, "It's so amazing! I am so happy you opened up about your struggles."
Cyrus teased that she was putting out new music earlier this week when she posted a selfie inside a sound studio.
After less than a year of marriage, news broke last Saturday that Cyrus and Hemsworth had separated.
“Liam and Miley have agreed to separate at this time,” Cyrus’ rep told TODAY in a statement.
“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.”
While Cyrus is seemingly using her music to speak out about their relationship, Hemsworth used his own social media to make a statement.
Earlier this week, "The Hunger Games" actor posted a message addressing the matter to his nearly 14 million followers on Instagram.
"Hi all Just a quick note to say that Miley and I have recently separated and I wish her nothing but health and happiness going forward," he wrote. "This is a private matter and I have not made, nor will I be making, any comments to any journalists or media outlets. Any reported quotes attributed to me are false. Peace and Love."