Shadowhunters Star Katherine McNamara in Two-Piece Workout Gear Says "Dive In"

Katherine McNamara is scuba diving – and posing in her exercise gear. In a new social media post the Shadowhunters stars flaunts her amazing figure in a swimsuit and workout gear during a scuba diving trip in the tropics. "We've got the right #PADI-tude and are feeling fin-tastic today! 🤿 Shore can't wait for you to sea @thequeensjewelsmovie. 🏴‍☠️💎 So, water you wading for, let's get kraken and dive in, shall we? 🐙 🐠 🌊," she captioned the series of Instagram snaps. How does she approach diet, fitness, and self-care? Here are her top diet and fitness tips.

As an actress, Katherine is no stranger to shaping up fast for a role, which takes discipline. She had less than four weeks to transform her body from "this ballerina, lithe-limbed body to a marine—and then on top of that, be ready to do all of this fighting and stunt work this film required," she told Women's Health about how she got in shape for Air Force One Down. "I just dove in headfirst into all different kinds of training and really worked hard. But it paid off in the end."

Katherine is no stranger to twice a days – exercising once in the morning and another round in the evening) prior to filming. "When you're doing a day of stunts on set, it's like being a dancer," she says. "It's over and over and over again in these 30 to 60-second spurts of super intense, maximum-effort fighting," she said. When the movie started filming she would wake up at 4 a.m., do an hour on the treadmill or bike for an hour, and then another hour of weight training. After a 13-hour work day she would return to the gym for another round of strength training.

"I think the most important thing I learned is: It's just get yourself there," Katherine recommends. "There were days when I was tired. There were days when the last thing I wanted to do was pick up a weight…but I just had to physically get myself there—to take a deep breath and remember why I was doing it and why I was there. I think that can go for any kind of physical goal that someone has—half the battle is the mental battle."

Katherine keeps her body fueled with health food, like chicken, vegetables, and scrambled eggs, and sometimes a potato, for carbs. "I just tried to stay pretty clean and get as much protein and fat as possible, to keep my body going but without having to work through anything processed," she says.

According to Katherine, to prep for her role as Clary Fray on Shadowhunters, she trained for intense fight scenes with HIIT workouts. "In order to do the fight scenes, I needed a lot of upper body strength because I would be holding weapons all day," she told Women's Health. "High intensity interval training turned out to be the perfect thing for me. I was able to keep up my cardio stamina and build upon that so I could do the fight scenes, which are basically just sprints." There is lots of research backing up the benefits of HIIT workouts, including body fat reduction, improved cardiovascular function, and mental health. It is also time effective.

Boxing also helped her get in fighting form. "It builds the shape of muscles I needed to look like a fighter, and it's just plain fun," she says. "I know most people hate leg day, but I kinda love it. It's what makes me feel strongest." Harvard Health maintains that boxing is a great way to build strength, improve balance, posture, hand-eye coordination, boost mood and endurance, and helps increase alertness.