Summer Stunners! Alessandra Ambrosio, Kylie Jenner, More Share Secrets For Looking Bikini-Ready Year Round

That explains it! The reality star, 23, recently revealed she’s been exercising twice a day, hitting the treadmill for cardio and Pilates machines for lengthening and toning. The beauty mogul clearly has a no pain, no gain mentality. "[Exercise] is hard," Kylie's confessed, "but it makes me feel good."

The pro dancer gets her workouts out of the way early in the day. "It doesn’t have to be high exertion, two hours, let's go," Julianne, 32, revealed. "But anything that gets me up and going. Sometimes it’s an hour and a half, sometimes it’s an hour, sometimes it’s 45 minutes."

The 24-year old It Girl says consistency is key when it comes to maintaining her fit physique. "Honestly, you just have to find something you like to do and do it often," Hailey's said. "Also, just do it even when you don’t want to — that is when you feel the best afterwards."

It’s all about the buddy system for January, 43, who prefers group classes to solo sweat sessions. "If there’s someone strong next to me, I definitely want to up my game," she revealed. "I think going [to the gym] with friends really motivates — you motivate each other!"

Winnie Harlow has admitted she’s not a huge fan of cardio. "I really don’t like it!" said the America’s Next Top Model alum, 26. "I prefer weight training. Pilates is a lot of fun too, as I love to stretch. I like to try new things."

Bella Hadid, 24, makes sure to fuel up prior to sweating it out. "I count on a smoothie, a juice or a protein drink 30 minutes before [a workout] session," the avid boxer has said. Afterward, it’s protein and healthy carbs. "[I'll eat] chicken and whole-grain rice," she explained. "It's ideal to [build] muscle mass."