The athletic guru had the actress working “like an animal” to prep for the role.

There is no escaping sweat when you’re with Hollywood personal trainer Gunnar Peterson, who is responsible for training the likes of Angelina Jolie, Kate Beckinsale and Khloe Kardashian and acts as director of strength and endurance training for the Los Angeles Lakers. He’s not one to skimp on time or get distracted, and he tends to be his clients’ biggest fans, a refreshing attitude in a world in which it’s all too easy to focus on negativity.

Peterson, who trained client Amber Heard for her turn as Mera in Warner Bros.’ superhero pic Aquaman, is as glowing as ever when talking about their journey. “You have to train the body as a whole,” the trainer said about how he approached the job, “shoring up any weaknesses — but the hardest part about that is finding any weaknesses on Amber!”

Peterson is a staunch believer that there’s “no magic pill” when it comes to attaining ultimate fitness, though the exercise guru-to-the-stars understands that for both superstars and non-actors, finding and harnessing time is often one of the biggest challenges. His workouts with Heard lasted an hour — “and they were a full 60-minute hour, make no mistake about it,” he said, adding that fitting these sessions into her already busy schedule was perhaps tougher than the physical work for “someone as athletic and capable” as the actress.

The focus was ensuring Heard’s strength in all three planes of motion, “and fluidity — see how I did that, since it’s an Aquaman movie?” quipped the workout developer, author and speaker. “And endurance is always key, not just for the character, but for the demands of the actual shoot as well.”

Heard also participated in fight training with another expert. “I’ve seen the trailer and I think it’s going to be a fun ride,” said the exercise buff.

The actress was all about bringing the best possible version of herself to the screen and into those figure-hugging ensembles, according to Peterson, and they went about that by zeroing in on movements and exercises that enhanced strength and flexibility. He also had Heard going through conditioning drills and dynamic movement patterns in pursuit of 360-degree fitness. She “worked like an animal,” said Peterson.

Since their work together for Aquaman, Peterson said he’s discovered MitoQ, a supplement that helps maintain energy levels on a cellular level, “helping your body get the most of your nutrition and oxygen, both of which are key components for sustaining energy and strength.”

Peterson’s go-to moves for the star included dumbbell squat presses, hip bridges (targeting the glutes and core) and shoulder endurance work on a Synergy Air Power Tower, which surely didn’t hurt the perfect posture to which her costumes cling. Anyone seeking a similar physique should do “all of the above and lots of it,” he said, as well as core work in all three planes of motion. “And don’t be afraid to lift weights — you are not going to get big from lifting. After all, Mera did it!”