Sam is currently on a break from the music industry and was spotted last night at a celeb party for the first time in months. The Spectre singer was barely recognisable, and debuted a slimmer frame. He previously said he lost a stone in a week through dieting, but has gone on to shed more and it has transformed his appearance since he stormed the music scene in 2012. Here, wearing a white top and baggy blue jeans, Sam has not just changed his weight, but also his image, and has ditched the suits he used to love. (Rex)

1. Gary Barlow Take That singer Gary Barlow revealed the results of an intense three-month weight loss program today ahead of the debut of his new TV show, Let it Shine. The star, who ballooned to 17 stone at his heaviest back in the 90s, revealed that the regime has been gruelling to get him in shape for his appearance. “Training was pretty intense. I’m 45 now, to go topless on TV is like, ‘I’m going to get in shape for this.” Further joking about his age, the singer added: “I wanted to look semi decent. I didn’t want the old moobs flopping away there!”

5. Jamie Theakston As far as transformations go, TV star Jamie Theakston’s was pretty epic. Part of a feature for Men’s Fitness magazine, the presenter got lean and ripped in just six months – overhauling his diet and seriously upping his exercise regime. Speaking about his achievement, Jamie said: “Don’t be afraid of the challenge. The hardest bit is the first couple of weeks. Then it keeps getting better.”

3. Chris Moyles After leaving Radio One, the then porky DJ decided it was finally time to focus on his health and slim down. Focusing on blasting fat with a strict diet and exercise regime, Chris managed to shed an impressive five stone. He admits he has the same weaknesses, saying, “I fall off the wagon sometimes and buy a pack of salt and vinegar chip sticks and a pack of cookies and eat them, and I feel bad about myself and cry myself to sleep. That happens. “It’s really, really, really hard to lose weight. I don’t care what anyone says. It’s easier to say than to do.” However, he now can’t imagine returning to his former self, saying: “I don’t know what I used to think when I looked in the mirror when I was at my worst.”

4. Craig David After going quieter on the music front, Craig David obviously got heavy in the gym. Following a move to LA, the Southampton-born musician honed his physique to pretty much male perfection. However, the singer has since confessed that his exercising got ‘out of control’ and that he has since chosen to tone it down since returning to music. “I’m not going to be that guy taking my top off at pool parties. I’m not about that any more,” he said.

10. Chris Pratt Chris had everyone’s jaw dropping when he morphed from Parks and Recreation geek to Hollywood hunk for his role in Guardians of the Galaxy. The now heartthrob who lost around 4 stone credits his new appearance on a low-carb Paleo style diet and intense CrossFit workouts. Asked after to give advice on how to lose weight, Chris said the key is to remain consistent. “All you have to do is just a few things everyday and remain consistent, and time will fly just as fast as it flies if you’re working hard or not,” he told interviewers.

12. Matthew McConaughey Matthew McConaughey’s transformation for his Oscar-winning role in Dallas Buyers Club saw the actor pushed to the point of starvation. The already trim star lost a staggering 3 and a half stone to play the role of an AIDs sufferer and called the experience ‘a spiritual cleanse’. “It was big transformation … it was a damn spiritual cleanse, man… [but] you’re reminded how often you think about the next meal through the day.”

15. Christian Bale When it comes to method acting, Christian Bale is your go-to guy. Whether it’s beefing up getting ripped, piling on the pounds or shedding them, it seems there’s nothing that the 40-year-old won’t do for his craft. However, the six-foot actor’s most extreme transformation came when he dropped to a skeletal eight and a half stone for his role in the 2004 thriller, The Machinist. Shockingly, he then only had six weeks to put on half this weight in muscle to start shooting Batman Begins. Hats off to the undisputed king of transformations.

13. 50 Cent You’d be forgiven for failing to recognise rapper 50 Cent who lost a staggering four stone in just nine weeks to play a cancer patient in drama, All Good Things Fall Apart. The musician turned actor showed serious discipline and commitment to the part revealing that he ran on a treadmill for an insane three hours every day and consumed a solely liquid diet. Someone give that man an Emmy, already. Yikes.

11. Chris Hemsworth After playing Thor, Chris Hemsworth is known for his killer body. However, after taking on the role of stranded sea captain Owen Chase in Heart Of The Sea the actor was put on what he calls a ‘starvation diet’ to leave him looking the part. Chris, 32, posted on Instagram at the time: “Just tried a new diet/training program called “Lost At Sea”. Wouldn’t recommend it..” The star revealed that to get into self confessed ‘scrawny’ state he cut his calorie intake to a measly 500 and cut out all weight training.

Jonah Hill – ’21 Jump Street’ The ‘Superbad’ comic slimmed down to play an undercover cop in the smash hit comedy with help from a nutrionist. “I just had a moment in my life where I said I wanted to become a man. And that means with my career that with my life, that means with my health.”

Matt Damon – ‘Courage Under Fire’ Damon was only required to look like a gaunt heroin addict for two days of shooting on Ed Zwick’s Gulf War drama, but he took no short cuts. He shed 50 lbs through running and a strict diet, but had to go on medication afterwards to repair damage to his adrenal gland.