Today, July 23, officially marks the four year anniversary of One Direction forming their band. We can't believe how much the guys have grown up in the years since their days on X Factor, and their maturity even reflects in their fashions. In the past four years, Harry Styles and Louis Tomlinson's hairstyles have grown into long manes, Liam Payne has gone from wearing polo shirts to rocking dapper suit jackets, Niall Horan had his braces put on and removed, and Zayn Malik got more tattoos than we can count!
Click through the gallery above to see how much each member of 1D has changed. Which guy's style transformation do you think is the most dramatic? Sound off in the comments section below!