Don't fret, you're definitely seeing double!

It's easy to think you know everything about A-list stars like Ashton Kutcher and Scarlett Johansson — but in reality, most people have no idea these two are twins!

MORE: Gisele Bündchen Shares a Throwback Photo With Her Twin Sister — See the Pic!

Click through the gallery below to see more celebs you didn’t know had twin siblings!