Do you remember what you were doing in 2010? The most popular song of the year was "TiK ToK" by Kesha (who still had a dollar-sign in her name), the highest-grossing movie was "Toy Story 3," and shows like "Lost" and "24" had just come to an end.Plus, some of our favorite celebrities of 2020 were just starting out in their careers, like Ariana Grande and Harry Styles, while others were already famous, but not as famous as they are today.

Keep scrolling to learn more about the 20 biggest celebrity transformations over the past decade.