Celebrity Heidi Klum Celebrates Her Birthday in a Teenie Weenie Bikini By Rita Kokshanian Rita Kokshanian Rita Kokshanian is a Los Angeles-based writer and editor who covers celebrity, fashion, beauty, and lifestyle. She was previously an Assistant Editor for InStyle and is currently the Senior Copywriter at The Grind. InStyle's editorial guidelines Updated on June 3, 2015 @ 01:45PM Pin Share Tweet Email Photo: AKM-GSI Now this is how you celebrate your birthday. Heidi Klum rang in her 42nd year in sunny St. Barts on Monday, where she proved that she doesn't look anywhere near her age in a sexy two-piece bikini. Klum, who was on the Caribbean island with her boyfriend Vito Schnabel, spent some time poolside in an Olaya Beach white, tan, and black bikini with a bandeau top and side-tie bottoms ($205, olayabeach.com). The Project Runway host topped off her look with a red-and-white baseball hat and oversized sunnies. But she isn't the only one who's been enjoying the sunshine in a bikini—from Jessica Alba to Kourtney Kardashian, see more celebs in their two-pieces in our gallery. PHOTOS: See More Celebrities in Bikinis