On Sunday, the "Golden Thing" singer took to Instagram Story to share a photo of Cyrus in honor of International Women's Day. In the tribute post, Cyrus can be seen holding an "M" cup while sticking out her tongue for the camera.
"Happy womens day to the strongest, most beautiful & extraordinary woman I've ever met," Simpson captioned the picture.
The "Mother's Daughter" singer went on to share Simpson's post on her Instagram Story, adding a black heart and skull emoji.
Earlier in the day, Simpson posted a video of him and Cyrus, along with a pal, dancing and singing together in a bathroom.
"Ya know," he captioned the video, taken by Cyrus.
It's been about five months since Cyrus, 27, and Simpson, 23, first sparked romance rumors. The couple raised eyebrows back in October when they were spotted kissing at a grocery store in Los Angeles.