If anyone knows how hard Shakira worked to prepare for her halftime show at the Super Bowl Halftime, it's Anna Kaiser.

The celebrity trainer and founder of AKT, a chain of dance-based fitness studios with locations across the United States, worked with Shakira to get her ready for her performance, which nearly 100 million people watched.

Kaiser was even with Shakira in October when the superstar found out she would be performing with Jennifer Lopez at the Super Bowl. And when it was time for the big show, Kaiser watched from the field below the stage.

Celebrity trainer Anna Kaiser, left, trained Shakira, right, six days a week leading up to the Super Bowl. Courtesy of AKT

"I was probably more nervous than she was," Kaiser told NBC News’ Know Your Value. "There were so many people, and it was so intense, but she just sinks right in and knows exactly what she's doing. It's so impressive to watch as someone who knows her as a human and mom, and to see her go from the giggly girl in the workout room to being in her element on stage."

Kaiser has been training Shakira for more than 10 years, and the singer is always preparing for something major, whether it's a world tour or television performance. To get ready for the Super Bowl, Shakira became even more active (hello, early-morning and late-night workouts)andcleaned up her diet (goodbye, extra sugar and dairy).Kaiser shared some of the ways Shakira primed herself for the performance of a lifetime:

No two workout sessions were the same

Leading up to the Super Bowl, Shakira trained six days a week, Monday through Saturday. Kaiser would alternate her workouts, focusing on dance-based interval training and full-body cardio one day and toning the next.

By switching things up, "you're challenging the body on various levels," Kaiser said. Shakira doesn't spot train, because it "really is about functional training, keeping it fun and working everything," Kaiser said. "Your body is not a combination of parts, it's a unit." On her Sunday rest day, Shakira didn't sit still — she would spend hours with her two sons doing everything from swimming to bike riding.

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Singer Shakira, left, with celebrity trainer Anna Kaiser, right. Courtesy of Anna Kaiser.

Shakira put her own twist on exercises

Shakira is known for her dance moves (her hips don't lie!), and that's a huge part of her workouts with Kaiser. "I'll bring her some dances, and she'll put her own flair on it," Kaiser said. "She can do things I couldn't do in a million years, because she's classically trained in belly dancing. It's really fun to see her make things her own and take it up a notch."

Kaiser — who got her start as one of Shakira's dancers — says dancing is a "great way to move in a proportionate way, so you don't overdevelop any muscles. You'll look like a long, lean, strong version of you." It also engages not just your body, but your brain as well.

Her diet was healthy, but never dull

Kaiser had Shakira cut out extra sugar, dairy, unnecessary refined carbs, and other inflammatory fare, and she concentrated on eating whole foods and high-quality lean proteins.

She ate small meals throughout the day to keep her energy up, because when you have "16 to 18 hour days, you have to keep yourself nourished," Kaiser said. Shakira also made sure to eat a variety of different meals, since "when you're bored, that's when you reach for things you ordinarily wouldn't, just to keep yourself interested," Kaiser said.

RELATED: How Anna Kaiser became the reigning queen of fitness

When she would train Shakira at her home in Barcelona, Kaiser packed her suitcase with foods not readily available Spain. "They don't have the same healthy foods, it's different, so I would bring macadamia milk or plant protein powder or tiger nuts," she said.

Shakira embraced her go-to exercise move

During her workouts, Shakira always found herself returning to one of her favorite Kaiser moves. "She loves my cobra arm series," Kaiser said. This twist on a tricep push-up "really activates every muscle in your arm, and you feel it immediately." It also improves posture, strengthening the back's middle muscles.

Her phone was on lockdown

Shakira's phone was MIA in themonths leading up to her Super Bowl show. There was so much to prepare for, "we were committed to keeping her phone off," Kaiser said. Shakira's priority is always her family, and she wouldn't pick up her phone in the morning until after she had time with her kids and got in a workout. "Details come flooding in, and you can lose focus," Kaiser said.

She always found a way to fit in workouts

When it comes to working out, it's all about consistency, but Shakira's busy life can sometimes make it hard for her and Kaiser to connect. Kaiser flies to Shakira's home in Barcelona for training, and they also do FaceTime workouts together. "I have to keep her motivated and really ready for anything," Kaiser said. Before the Super Bowl, they worked around Shakira's packed schedule, with no session too late — a few even started at midnight. "She's such a hard worker, and when she commits to something, she makes sure it happens," Kaiser said.

On days where Shakira didn't have a full 90 minutes to complete a workout, Kaiser would break it up, doing 15- or 30-minute sessions. "You have to go with the flow," she said. "Any working mom will tell you every day comes with different challenges, and my job was to be prepared and there to support her in the way she needed to be supported."

Celebrity trainer Anna Kaiser. Duke Loren

She took the time to celebrate life

The holidays didn't slow Shakira down, and she still made sure to celebrate with her family. "She was on a program and working hard to prepare," Kaiser said. "She took a break to see family and enjoy the holidays, and then got back into it. At that point, it's not about cramming for the exam, it's about studying and preparing for the longterm."

Finding balance is key, and so is knowing when to celebrate — Shakira's 43rd birthday coincided with Super Bowl Sunday, and "within 10 minutes of being off stage, she was in ripped jeans and a T-shirt with her family and friends, eating cake," Kaiser said. "She was reveling in the moment, and that's really important. It can be hard to take in all of that right away — you've had so many weeks of prep and all of a sudden, it's over and on to the next thing. She announced her world tour a few days later. It's constant — such is the life of a performer!"