28-year-old Liam took to Instagram to share a video with his fiancée as they larked about in a car on Thursday.
In the short clip, Miley is seen dancing in front of the camera while Liam screams to distract her.
The Aussie actor then shared footage of his prank to his 10 million followers.
Fans were delighted to see the on-off pair back in each other’s company after it was reported this week they had called off their wedding following alleged fights over when to have kids.
The pair – who first got engaged in 2012 – were alleged to have gone their separate ways after Miley is said to have kept delaying their wedding and family plans.