2. Jennifer Aniston
Jennifer Aniston is a celebrity who is not a twin among others in the list.
Only 3% of the world population are twins. And about 0.3% are identical twins.
From above list of celebrity, all share twin siblings except Jennifer Aniston. Ashton Kutcher, Scarlett Johansson, and Kiefer Sutherland, all have twin siblings.
Mary-Kate and Ashley Olsen are famous twins celebrity.