Britney Spears, Pink, and Janet Jackson have triumphed over their yo-yoing weight problems thanks to personal trainer Tony Martinez.
Tony helped rock star and mom of two Pink get back into shape by using a skateboard in her workouts.
And he helped 33-year-old Britney regain her youthful toned look ahead of her hugely successful residency at the Planet Hollywood in Las Vegas.
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Getting it back: Tony Martinez helped Britney Spears get in shape for her hugely successful residency in Las Vegas, pictured on left at the Billboard Music Awards in May and on right performing in London in 2009
Before that the 47 year old LA native helped Janet Jackson stun millions with her controversial 2004 'Nipplegate' half-time performance at the Super Bowl alongside Justin Timberlake.
He's got all the secrets! Tony has been training celebs for nearly two decades
His 'workout smarter, not longer' philosophy also helped Janet lose an incredible 60lbs in four months to appear on front cover of Shape magazine.
But out of of the three icons, Tony says Pink is without doubt his 'most competitive' client, saying: 'I call her an athlete entertainer.
'She's very athletic. We would do stuff on a skateboard because she use to be a skateboarder, she loves that. She's a good athlete.
'I'd also make her do fun stuff on a trampoline afterwards, then get back on the skateboard.
'She was on the skateboard doing lateral raises, it was amazing!
'I have to be creative to keep her on her toes.'
Two years ago Tony prepared Britney for her ongoing Las Vegas residency which kicked off December 2013.
Britney wanted to be as toned as possible for her Vegas shows, which she accomplished with 'intense' workouts three to four times a week for 40 minutes.
Tony revealed: 'She loves all core workouts. She's a very tenacious women. She wants to get it done and get it done right.'
What are some of Britney's favourite core exercises? Tony explained: 'We use my core discs.
'Core discs are little circle things that I had made up for my product and we use those for a lot of ab workouts. We use those for mountain climbers, will do a barrel role tuck in where you turn around all the way over and then you bring your knees in. So really functional exercises that she likes, and she's like, "I really feel this."'
Tony also helped the singer clean up her diet to compensate with her grueling workouts.
Changing body: The star pictured in 2009 performing in Melbourne, Australia was a bit fuller figured than nine years before (on right)
She got it back: Britney looked slim and gorgeous in early May at the Billboard Music Awards in Vegas, pictured with her Pretty Girls collaborator Iggy Azalea
He explained: 'I pretty much just wanted her to balance out her proteins, carbs, and fat. Everything pretty balanced in that aspect because she was doing a lot of cardio so I wanted her energy up the whole entire time.
He added: 'She loves to run, but I would make her go backwards.
'She's like "I'm gonna go backwards?'"I'd be like "Yeah let's go on the treadmill and walk backwards." She'd be like, "I could lose my hamstrings and my glutes. What are you doing to me!?"'
Tony also revealed the singer's 'hidden' talent, saying: 'She's a very very very good tennis player.
'She hit the ball 108 times nonstop until I hit the ball in the net and she was like, "Are you kidding me!?", I'm like, "I'm sorry." So I messed it up!''
Yo-yo dieting: Pink got toned with the help of the celeb trainer, pictured on left at the Grammys in 2010 but seemed to bounce back (on right) in April this year
The trainer also dished on Britney's softer side, adding: 'She's just like a regular person. Really nice, just really sweet girl.
'She just has a great sense of humor. She's just funny and likes to crack jokes.'
Tony's longest-standing client is pop sensation, Janet, 48, who he's been working with since 1997.
He calls her preparation for Shape magazine's special October edition cover in 2001 - where the superstar had to lose 60lbs - his 'proudest moment'.
He explained: 'My best reward was when Janet was on Shape magazine.'
Huge weight loss: Martinez helped Janet Jackson shed 60lbs in four months, pictured on left in March 2001 and on right in July 2000
It seemed an impossible feat, but Tony accomplished Janet's goal - and did so in record time.
He revealed: 'She had to lose 60-pounds and we did it in four-months. I mean, it was hardcore workouts. She was just focused!'
His secret? He explained: 'I amp up a lot more cardio. We did two-a-days, cardio, and eating very, very clean. Smart nutrition is half the battle.
'We pretty much just upped her protein a little bit more and gave her good carbohydrates instead of bad carbs. I gave her more whole grains, sweet potatoes, brown rice, but a lot more vegetables, and she had no problem with that, the weight just came right off of her no problem.'
Tony admits that as Britney, whose mom to Sean Preston, nine, and Jayden James, eight with ex-husband Kevin Federline, gets older he's had to adapt the workouts.
Core work: The trainer claims that Britney's favourite workout is on her core with his specially designed discs
He explained: 'I don't make it as strenuous as when they were younger. So I basically do a little more rehab as well too. Shoulders, the knees, hips, back, and a lot more stretching as well.'
To battle yo-yoing weight, Tony says it is vital to make realistic goals.
He explained: 'Don't say right away, "Alright, I'm going to lose ten pounds in one day." I get that all the time. Just take it slowly. Anywhere between a pound to three pounds a week is perfect.'
Above all, Tony admits his main goal as a trainer is giving his clients quick and effective workouts that they enjoy so they will come back wanting more.
He said: 'I think if anything it's just helping these people realize that they can do this, you give them the motivation. I'm not a military guy, I don't yell and scream. I try and joke around with them so they can have fun and make them believe that they can have a good time working out.
'I try to make it fun so they don't realize that they're doing it. So basically I trick 'em. I trick 'em into having fun and it works.'
Diet is key: Tony says that eating correctly is over half the battle
