Fashion Happy Birthday, Bikini! See Stars in Their Teeny-Tiny Swimsuits By Alexis Bennett Alexis Bennett Alexis Bennett is a New York-based writer who covers all things fashion, shopping, and beauty. She was previously the Ecommerce editor at InStyle. InStyle's editorial guidelines Updated on July 5, 2017 @ 01:30PM Pin Share Tweet Email Photo: lupitanyongo/Instagram There's no season quite like summer to celebrate the bikini! The two-piece swimsuit may have been popularized on July 5, 1946, but there's actually proof that the sexy styles were worn during the 4th century—according to Roman mosaics at least. But in the modern era, it took years for the scandalous fashion to really catch on. It wasn't until the effects of war rationing caused the United States government to order manufacturers to cut back on the amount of fabric used to create swimming suits. (See, fashion and function do get along!) Louis Réard, a French engineer, recognized an opportunity to capitalize on the itsy-bitsy pieces and coined the new look the bikini. Ever since two-piece swimsuit has continued to evolve into a staple and summertime must have. VIDEO: The Evolution of the Swimsuit We've seen modest versions emerge like the tummy covering tankinis and daring silhouettes like the revealing mini micro bikinis. And although some of the unique bikini trends may not have withstood the test of time, the two-piece swimwear look has become a classic—not to mention the look celebs wear when posting Instagram pics of their toned bikini bodies. How to Find the Right Swimsuit for Your Body Type In honor of the iconic style's official birthday, we've gathered a gallery of our favorite stars showing off their beach-ready style. Click here to see how the celebs dress for some waterside fun.