You may know that Amy Schumer, the actress-producer-writer-comedian, is both hilariously brilliant and superbly outspoken on women's issues - but did you know that she's also a certified kickboxing instructor?

Yep, she is pretty bad ass.

Plus she's also used her qualification to teach classes in yoga, Pilates, spin, step, and dance.

Schumer had to get into even better shape for her role in Trainwreck. And to do this she roped in the famous celebrity trainer, Harley Pasternak. And Schumer isn't the only super-fit star that Pasternak has helped stay in shape.

His past A-list clientele has stretched from Lady Gaga to Halle Berry and Jessica Simpson. And Pasternak has also had a hand in how pop princess Ariana Grande keeps trim.

Pasternak spoke to us exclusively about the diet and exercises that he uses to keep both Schumer and Grande in tip-top shape.

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Staying fit: Personal trainer Harley Pasternak works out celebrities such as Amy Schumer (left) and Ariana Grande. He says his favorite workout for Schumer to do is spinning while he has Fitbit 'competitions' with Grande

The Canadian-born trainer and nutritionist has a Masters of Science in Exercise Physiology and Nutritional Sciences.

As well as training Hollywood's elite, he has also spent time in the past serving as an exercise and nutrition scientist for Canada's Department of National Defence.

We asked him exactly what his tips and tricks are for keeping celebs in shape. The good news? He says a celebrity body is attainable for anybody.

Q: What kinds of exercises do you do with Amy Schumer?

Amy is super athletic and stays active all the time. Recently she's incorporated some spinning into a routine, but mainly she does a great resistance circuit called the Sinful Seven, where I combine seven different strength movements and to continue a circuit

Q: And how about Ariana Grande?

Ariana is my Fitbit nemesis - somehow she manages to just outstep me each day. She's always dancing on tour, and staying active, and we incorporate very simple resistance move supersets into her weekly routine.

Q: What are their favourite workouts?

I'm not sure they have favourite workouts but both of them have a really high pain threshold, which is great. While they exercise I also keep telling them fascinating stories to keep them distracted from the intensity of our workouts.

Pasternak said anyone can get a A-list body because: 'To get a celebrity body just means you work as hard as they do and eat as clean as they do'

Q. How many times do they train per week?

It completely changes depending on their schedule, but they stay active every single day.

Q: How long are their sessions?

Their sessions last between 30 and 45 minutes.

Q: How hard do you push them?

Just hard enough, they should still be able to carry on a conversation, though.

Q: What kind of diets do they both follow?

I try and get them to eat three meals and two snacks a day. I incorporate some Body Reset Diet smoothies into their routines (straight from Pasternak's book, this diet is packed with metabolism boosting smoothies).

Each meal has a protein the mass of their hand, unlimited vegetables, water soluble fibre that fits in the palm, and at least the mass of the thumb of healthy fats.

Q: What is your number one tip for dieting?

You need to make sure you have protein, fibre, and healthy fat at each meal.

Q: Are there any foods you limit or eat more of?

I tell my clients they have two 'free meals' a week where they can eat whatever they like, otherwise we focus on the nutrients I mentioned.

Q: If you have a cheat meal, what is it and how often do you eat it?

Chocolate chip cookies! But I'm not telling you how often.

Q: Can we all have celebrity bodies?

Celebrities are just normal people with interesting jobs, they don't have any physiological differences than anyone else.

To get a celebrity body just means you work as hard as they do and eat as clean as they do.

Comedienne Amy Schumer is a certified kickboxing instructor - a skill she used when training with Pasternak to get in shape for her movie Trainwreck

Q: What is your most reliable type of go-to exercise?

Walking. You can do it anywhere and anytime, with friends or with co-workers or by yourself, and it requires no special equipment.

Although I do strongly recommend you get yourself a Fitbit to see how many steps you take (it should be at least 10,000).

Q: What is your favourite type of fat busting exercise?

Still walking. Because you can do lots of it, throughout the day, you don't need any equipment to do it, and the leanest people in the world also walk the most.

Q: What is your favourite strength exercise?

I love the walking lunge. I like that you're travelling from one point to another, and using a lot of your lower body.

Pasternak posted this photo of Grande last week showing off her slim body

Q: What ratio of cardio – weights do you advise?

I don't think of it in terms of ratio. You need to hit at least 10,000 steps every day of your life. That's aerobic. Resistance-wise, it depends on who you are and your goals, but I suggest doing 10 to 30 minutes three to five days a week.

Q: What is your number one way of keeping your clients motivated to continue a workout?

I don't believe you can meaningfully motivate anybody. I believe we are already motivated, and just need the simplest and most comfortable ways to achieve our goals.

Q: What do most of us get wrong when we aren't seeing results?

You're either not moving enough throughout the day, not eating clean enough, or maybe not sleeping well enough.

This article was originally published by Healthista