Of course, this isn't the first time the 28-year-old Killerman star has pulled something like this on Cyrus. In fact, it's kinda his thing!
Earlier this month, Cyrus posted a video to her Instagram Stories of the two in the car, jamming out to 21 Savage's "Bank Account." All was fine, until Hemsworth yelled, "Oh s**t," and pretended to lose control of the vehicle.
And let's not forget about the time he scared her while singing along to a Justin Bieber song:
While Cyrus and Hemsworth have no problem joking around with each other in person and on social media, the lovebirds have been "very secretive" about their plans to tie the knot.
A source told ET last month that although they've been engaged for a few years now, only now do they feel ready to get married. "They have been in love for almost nine years, but the timing has never been right until now," the source said at the time. "Their massive careers, their ages and their families' input has kept them from getting married."
"Miley has come up with all sorts of different wedding plans," the source added. "She is always creative and thinking of new ideas that will make her experience different, but recently she decided she would make it simple. She hasn't announced anything because she is being very secretive, so only their friends will know and at the very last minute. This time they are doing everything their own way."