When it comes to fitness, we usually assume a celebrity owes their fab physique to a personal trainer—but sometimes they are just like us and head to a group class. Whether ballet-inspired,  military-style or like Pilates on steroids, here are a handful of workouts with cult-like followings where you’re likely to spot a sweaty celeb.

Solidcore

Haven’t heard of Solidcore yet? Get ready to hear a lot more about it because this East Coast-based high-intensity, low-impact, controlled-movement work-out is rapidly expanding. The centerpiece of the fitness experience is the Sweatlana—which may look like a Pilates transformer at first glance (but you quickly learn it’s not). With super-peppy instructors who literally work your muscles to failure during each 50-minute class, word has it that Michelle Obama is a regular at the Washington, D.C. studio.

Pure Barre

Utilizing the ballet bar and upbeat music, this fitness class focuses on small, precise movements that add up to a full-body workout that strengthens and lengthens muscles while targeting stubborn spots like the hips, thighs, tush, abs and arms. Celebrity devotees like Britney Spears, Anna Kendrick and Maria Menounos love the concentration and mindfulness required for the technique, which is said to provide meditation-like mental benefits as well. Best of all, Pure Barre has studios across the country as well as on-demand streaming when you want to get your fix on your own time.

Physique 57

What do Demi Moore, Chrissy Teigen and Selena Gomez have in common? They’ve all professed their love for (or rather, obsession with) this workout that uses your own body weight to deliver enhanced muscle definition, strength and overall fitness. Each class is designed to work your muscles to exhaustion before giving them a deep stretch—and produce results you can see in as little as eight workouts. And if you can’t get to one of their studios in NYC, the Hamptons, Beverly Hills, Dubai or Bangkok, you can stream classes in the privacy of your own home.

LEKfit

The brainchild of professional dancer and choreographer Lauren Kleban, this mix of low-impact, high-intensity, fat-burning cardio and muscle sculpting offers a fun yet challenging workout fueled by music that makes you want to move. Though based in Los Angeles, classes can be streamed anytime and anywhere so you can sweat like Michelle Williams and Busy Phillips regardless of where you live.

Tracy Anderson Method

Gwyneth Palthow and her long, lean, lithe physique may have made Tracy Anderson somewhat of a celebrity in her own right, but this intense fitness obsession counts Victoria Beckham, Sienna Miller, Nicole Ritchie and countless others as fans. This dance-driven, sweat-inducing workout burns fat, targets smaller muscles to create major definition without the bulk—and you can even take part via streaming if you don’t reside near one of the NYC, L.A., Hamptons or Madrid studios.