The picture shows Hemsworth smiling for a selfie as Cyrus and Bean look off into the distance. Mary Jane can been seen farther up on the path.
"Strolls with my girls," Hemsworth captioned the post.
Hemsworth followed up with a video of himself pranking Cyrus in the car. He wore a camouflage mask while driving and suddenly braked to scare the 25-year-old singer.
"Gets her every time," the star wrote.
Cyrus and Hemsworth reconciled in January 2016 after ending their engagement in 2013. TMZ reported this month the couple may never formally marry, although sources said the pair's relationship is stronger than ever.
"They're perfect for each other," an insider said.
Hemsworth is known for the Hunger Games movies, and will next star in the film Isn't It Romantic with Rebel Wilson. Cyrus last released the album Younger Now in September.