Cyrus posted four pics in all, one that reads, "10 years later," alluding to how long they have been together.
The pics are all black and white and show the actor wearing a traditional groom's tux, while Cyrus has on a white dress. You can also see a ring on Hemsworth's finger in one of the pics.
There's also one of them kissing.
Cyrus also posted a video of the couple jamming out to "Uptown Funk," the bride lip syncing to the Mark Ronson hit.
Reports the couple had gotten married came after surfer Conrad Carr posted a video to his Instagram story of the Hemsworth brothers taking what looks to be a shot together and in the background, you can see "Mr. and Mrs." balloons.
MILEY AND LIAM ARE MARRIED. THEY GOT MARRIED. CONGRATULATIONS TO THEM pic.twitter.com/71evxCJXSn— lou (@nosensesu) December 24, 2018
Later, Carr posted a picture of Cyrus in a white dress, holding Hemsworth's hand, cutting a large, fancy cake.
A request for comment from Cyrus and Hemsworth's reps were not returned to ABC News.
Hemsworth, 28, and Cyrus, 26, met on the film "The Last Song" and dated for three years before getting engaged the first time in 2012. They broke things off the next year but got back together in 2015. They got engaged again the following year.
In November, Hemsworth wished his love a happy birthday, writing, "You’re more precious than ever. So thankful to have you in my life."