In addition to famous Twins like Mary-Kate and Ashley Olsen, Benji and Joel Madden, and the Mowry sisters, there are a number of Celebrities that you may not have known are part of a pair. Ashton Kutcher, Scarlett Johansson, Gisele Bündchen, and even Vin Diesel have twin siblings - and while some of their other halves keep a low profile, others have a place in show business as well. Keep reading to see 16 stars that you didn't know had a double!