Demi Lovato caught one special celebrity by surprise during a recent trip to New York City!
Lovato was shouting from her car, telling fans on the sidewalk to go out and buy her latest album, Demi, when she happened to stop next to none other than Ben Stiller.
After spotting the famous actor, the "Heart Attack" singer screamed: "Ben Stiller, buy my new album on iTunes! It's out now, it'll give you a heart attack."
Lovato herself was so shocked by the sighting that she began laughing and said, "F--k yeah!" to her friends in the car afterward.
We bet Stiller definitely got the album after that run-in!