Looking ship shape! Mariah Carey's squeeze James Packer flaunts slimmer physique as he undergoes gruelling training session on board his superyacht

He's has spoken openly about his battle with the bulge after undergoing gastric band surgery in 2011.

But casino billionaire James Packer, 47, seems to have got a handle on his fluctuating waistline, ever since he stepped out with Dream Lover Mariah Carey, 45, thanks to diligently working out.

The Australian businessman struck a slimmer and more toned physique to recent times as he was seen lifting weights with the guidance of a trainer on board his superyacht on Thursday.

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Look at me! Billionaire James Packer showed off a more toned physique to recent times as he worked out with a trainer on board his super yacht on Thursday

Look at me! Billionaire James Packer showed off a more toned physique to recent times as he worked out with a trainer on board his super yacht on Thursday

Al fresco training: The casino billionaire appears to have got a handle on his fluctuating waistline since stepping out with relatively new squeeze Mariah Carey

Al fresco training: The casino billionaire appears to have got a handle on his fluctuating waistline since stepping out with relatively new squeeze Mariah Carey

A shirtless James executed bicep curls, squats and various weight exercises as his trainer barked instructions on the deck of the multimillion-dollar Arctic P.

As the sun gently sank, Australia's fourth richest man dutifully worked out and at one stage appeared so exhausted he knelt down on one knee to regain his breath.

Wearing just a pair of navy boardshorts, the towering mogul showcased a deep tan, an acquisition from a protracted holiday sailing around the Mediterranean.

Ouf! An exhausted James had to kneel down at one stage to regain his breath mid training session

Ouf! An exhausted James had to kneel down at one stage to regain his breath mid training session

Up he gets: The 47-year-old was soon back on his feet for the next round of exercises

Up he gets: The 47-year-old was soon back on his feet for the next round of exercises

A work in progress: The casino mogul has been religiously working out since meeting diva Mariah Carey
A work in progress: The casino mogul has been religiously working out since meeting diva Mariah Carey

A work in progress: The casino mogul has been religiously working out since meeting diva Mariah Carey

Once recovered, he leapt to his feet for the next set of exercises and as the endorphins rushed around he punched the air in a jubilant manner.

James, who last month quit his role as casino company Crown's chairman but will remain on the board of the company, was recently overheard boasting of his weight loss in his corporate box at Lord's Cricket Ground.

The Daily Telegraph reported him as saying, '[I'm] 96 kilograms and as fit as I've ever been.'

The way it was: The gambling billionaire pictured in Sydney in 2008 when he was decidedly rounder

The way it was: The gambling billionaire pictured in Sydney in 2008 when he was decidedly rounder

Focused: His trainer Damien Chapman is the man credited for shaping the billionaire

Focused: His trainer Damien Chapman is the man credited for shaping the billionaire

Do it like this: The Australian mirrored his trainer on the deck of the yacht

Do it like this: The Australian mirrored his trainer on the deck of the yacht

Working it: James jokingly told friends he planned to celebrate the milestone by walking down Sydney's iconic Bondi Beach in nothing but his Speedos to parade his newly chiselled six-pack

Working it: James jokingly told friends he planned to celebrate the milestone by walking down Sydney's iconic Bondi Beach in nothing but his Speedos to parade his newly chiselled six-pack

The publication also speculated that the media magnates' new physique is the result of a new workout regime with trainer Damien Chapman who James is believed to have invited on his latest Mediterranean jaunt with singer Mariah.

James' battle with weight has been well documented. In 2011 James - who once weighed 130kg- underwent gastric bypass surgery at a clinic in Los Angeles, losing 40kg.

Letting it hang loose: The father of three has been honing his physique and invited his trainer on board his yacht 

Letting it hang loose: The father of three has been honing his physique and invited his trainer on board his yacht 

Stay strong: Bathed in golden sunlight, he took time to work out

Stay strong: Bathed in golden sunlight, he took time to work out

Lift! Mariah Carey's squeeze performed numerous bicep curls 

Lift! Mariah Carey's squeeze performed numerous bicep curls 

The next year he embarked on a weight-loss regime so strict he promised friends he would hit his target weight of 90kg by December 1, 2012.

He jokingly told friends he planned to celebrate the milestone by walking down Sydney's iconic Bondi Beach in nothing but his Speedos to parade his newly chiselled six-pack.

James has been looking trimmer since he found love with Mariah and their relationship appears to be going from strength-to-strength with the magnate telling News Corps Australia: 'Mariah is just incredible, amazing she really is...She’s a genius'.

Gruelling: He cut a decidedly slimmer figure from 2011 when he was so overweight he needed a gastric band operation

Gruelling: He cut a decidedly slimmer figure from 2011 when he was so overweight he needed a gastric band operation

Less play, more work: There was time for a little chatting between work sets

Less play, more work: There was time for a little chatting between work sets

Too heavy? At one stage James looked a little overwhelmed by the heavy weights

Too heavy? At one stage James looked a little overwhelmed by the heavy weights

Showing him how it's done: James demonstrated how to hold the dumbbell

Showing him how it's done: James demonstrated how to hold the dumbbell

Gushing about his love interest, he went on: 'Who else is there? There is Barbra Streisand, Whitney Houston and Mariah Carey. Not Madonna...Those three can sing five octaves...'

James was seen at the side of the stage when the diva performed in Tel Aviv weeks ago stomping his feet and cheering and clapping.

And when she crooned the words 'glad I found you' from one of her hits, she glanced deliberately at his beaming face.

Like this? Then it was the businessman's turn to show what he was made of

Like this? Then it was the businessman's turn to show what he was made of

Hard core: The pair worked out as the sun set in the distance
Hard core: The pair worked out as the sun set in the distance

Hard core: The pair trained as the golden sun set in the distance

Keeping firm: He cut a slimmer silhouette and held his core tight

Keeping firm: He cut a slimmer silhouette and held his core tight

Weeks earlier the pneumatic singer, who has a residency at Caesars Palace Colosseum, Las Vegas, dedicated her hit song Hero to her new flame.

She told the audience: 'I have a new heart tonight' as the crowd whooped and cheered.

Mariah continued: 'James is in my heart tonight.'

Last set: A few more weights and James was almost done

Last set: A few more weights and James was almost done

Is it over yet? The pair wound down after what appeared to be a gruelling session

Is it over yet? The pair wound down after what appeared to be a gruelling session

Grrrh: Clenching his fists tight, the Sydneysider struck a defiant pose

Grrrh: Clenching his fists tight, the Sydneysider struck a defiant pose

The blossoming pair had a very public unveiling as a couple when they enjoyed a Mediterranean trip several months ago.

They spent time together sailing around the Balearic Islands, including Ibiza and Formentera, on James super yacht Artic P. 

Sources close to the songstress told TMZ the father-of-three had been 'aggressively' pursuing her and was 'obsessed' by her music after meeting at her concert in Las Vegas in April.  

Dream Lover! The media magnate was recently seen holidaying with Mariah Carey and business partner Brett Ratner and Kevin Tsujihara

Dream Lover! The media magnate was recently seen holidaying with Mariah Carey and business partner Brett Ratner and Kevin Tsujihara

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