Rihanna is one hot singing sensation. Having recently been named the best-selling digital artist of all time-thanks to a whopping 47.5 million downloads of her hits-the sexy songstress is also a top contender for "Album of the Year" at this year's Grammy Awards.

But not only does the Barbadian beauty know how to rock a stage, she also rocks a bikini, too! No stranger to showin' off some skin, getting that taut and tight tummy definitely takes work.

That's where inspirational fitness expert extraordinaire Ary Nuñez comes in; she's been training the artist hard for almost four years. "We focus on the core muscles, and we do a ton of repetitions," Nuñez says.

Rihanna is as dedicated to her workouts as she is her singing career. "Working with an artist like Rihanna has different demands than most," Nuñez says. "We train when she's ready…even if we're on the road and it's 2 a.m. in the morning. I'm on call 24/7 with her."

Nuñez, who has worked with scores of celebs and professional athletes (she's a kick-butt Nike sponsored athlete herself), trains Rihanna using a mix of martial arts, dancing, and calisthenics.

"Rihanna is so connected to her body. She used to work out because it was part of her responsibility, but now she works out because she loves it!" Nuñez says.

The talented trainer also works with the singer to make sure she's fueling her body with what it needs while touring or on set. "It's more about feeding her to perform," Nuñez says. "She is big on protein-she loves it."

When it comes to Rihanna's diet, Nuñez promotes proper food combining. "You shouldn't mix starches with protein because there is an enzyme that exists for the processing of starches, and an enzyme that exists for the processing of protein-and they don't get along," Nuñez says.

"Can you imagine two enzymes having a fight in your belly? One is going to win and stay. If it's starch, it turns to glucose-not good. If it's protein, it turns to fat-also not good."

A typical meal for the newly crowned queen of the digital universe? "Fish with a salad or veggies," Nuñez says.

So while we all may not be able to rock a stage like Rihanna, we can still get her rock-hard abs! We were thrilled when Nuñez shared one of RiRi's abs workouts with us (I think 'we've found love' with this routine, btw!) Check it out on the next page!

You'll Need: An exercise mat, some hot Rihanna tunes, and major girl power!

Full-Range Sit-Up

Start with your back on the floor with your heels secure, shoulder width apart. Leading with your chest up towards the ceiling, use the spine as it is in neutral position. Drive all the way up with your chest and once you reach your knees, extend your arms up and straight overhead. Your shoulders should be directly over your hips.

Complete 32 reps.

Sit-Ups with Torso Rotations:

Lie on your back with your right ankle resting on your left knee. Your right arm is placed on the floor out to the side. Keeping the right shoulder down, curl the left shoulder up to the right knee. Repeat with opposite limbs.

Complete 32 reps on each side.

Holding Plank:

Begin in the plank position with your forearms and toes on the floor. Keep your torso straight and rigid and your body in a straight line from ears to toes with no sagging or bending. Your head is relaxed and you should be looking at the floor.

Hold this position for 32 seconds, repeat 3 times.

Active Plank:

From plank position, take your right hand, lift it from the floor and drive it into yourself (forward and back) like you're tapping the floor. Think about the elbow striking something behind you.

Complete 32 reps on each side. Believe us, you will be exhausted.

Roman Rotator

Stand in a horse straddle, with your feet parallel in a wide squat position with your back flat. Take your arms and lift your elbows to shoulder height. Rotate left to right, right to left.

Do this one till you're working up a major sweat!

For more great Ary Nuñez workouts, download the Nike Training Club (NTC) App from iTunes (no excuses, it's free!). "All the exercises are incredible, and you get all the visuals too," says Nuñez. "The more minutes you work out, the more routines you'll be able to unlock-and I'm already a Black Belt!"


Kristen Aldridge lends her pop culture expertise to Yahoo! as host of "omg! NOW." Receiving millions of hits per day, the hugely popular daily entertainment news program is one of the most-watched on the web. As a seasoned entertainment journalist, pop culture expert, fashion addict and lover of all things creative, she is founder of and recently launched her own celeb-inspired fashion line and smartphone app. Connect with Kristen to talk all things celebrity via Twitter and Facebook, or visit her official website.