A dedication to fitness is essential for a celebrity-worthy physique, and an intense workout routine is non-negotiable. Sure, personal trainers and chefs definitely help attain awe-inspiring abs and arms, but the below workouts have dedicated bold-faced followings in Hollywood and beyond.

The workout: Tracy Anderson Method
The devotees: Gwyneth Paltrow, Madonna, Jennifer Lopez, Nicole Richie, Courteney Cox, Victoria Beckham
The details: With a big emphasis on dance moves—and sweating—Tracy Anderson’s fitness approach targets smaller “accessory” muscles to garner major results. Whether you pop into one of her seven studios in New York, Los Angeles or London, participate in streaming classes online, or commit to one of her 90-day Metamorphosis DVD exercise and diet programs, “The Method” requires up to two-hours a day for optimal body transformation, but Anderson’s laundry list of celebrity clients can’t get enough. (Anderson also has one of the strongest fitness-fashion games in the biz, and we hear her go-to brand is Liquido Active.)

The workout: The Class by Taryn Toomey
The devotees: Jennifer Aniston, Christy Turlington, Naomi Watts, Gisele Bundchen
The details: Taryn Toomey is all about fitness for both the body and the mind, and her “cathartic movement experience” includes cardio, yoga and strength training with a steady stream of spirit-boosting affirmations. With studios in New York City, Los Angeles and Vancouver (as well as seasonal classes in the Hamptons and Nantucket), The Class can be enhanced with nutritional programs and retreats that anyone, anywhere can participate in.

The workout: Body by Simone
The devotees: Rosie Huntington-Whitely, Reese Witherspoon, Lily Collins, Chrissy Teigen, Taylor Swift, Gigi Hadid
The details: Former dancer and native Australian Simone de la Rue started a movement (no pun intended) when she opened her first fitness studio in New York City in 2011. She’s since added two locations in Los Angeles, where clients get their fix of high-intensity dance cardio and light-resistance weight training that keeps them going back for more. The good news is, those between coasts can get their body-changing groove on with de la Rue’s Body by Simone DVDs, as well as monthly or annual video streaming subscriptions.

The workout: AKT in Motion
The devotees: Kelly Ripa, Shakira, Sarah Jessica Parker, Drew Barrymore, Hilary Duff, Karlie Kloss
The details: If you have a hard time deciding between circuit training, HIIT, strength training, dance cardio, Pilates and yoga, then Anna Kaiser’s AKT in Motion might be the ideal fitness solution for you. There’s no yelling and classes are revamped every two to four weeks to keep workouts challenging—but AKT boasts a “torture-free” environment so although you may be a bit sore the next day, you should still be able to sit down and stand up. In addition to studios in New York City, East Hampton, Connecticut and Los Angeles, AKT offers “on demand” subscriptions so you can stay fit anytime and anyplace.

The workout: Barry’s Bootcamp
The devotees: Kim Kardashian, Katie Holmes, Jessica Biel, Amanda Seyfried, Katie Couric
The details: This butt-kicking interval-training class combines treadmill running and resistance training with the help of kettlebells, elastic bands and body bars—and an upbeat playlist that helps keep you going. Monday through Thursday classes target a different part of the body (i.e. arms and abs, butt and legs or chest, back and abs) while Fridays, Saturdays and Sundays serve up a full-body workout—just be sure to give yourself time to recover. With studios in New York, California, Miami, Atlanta, Chicago, Boston, Nashville, Dallas, and D.C. (as well as Europe and the Middle East), this fitness phenomenon can burn up to 1,000 calories a class if you give it your all.