Celebrity shape-shifters

Beyonce Knowles

The singing sensation dropped a reported 20 pounds to play the role of Diana Ross in Dreamgirls using the Maple Syrup Diet also known as Master Cleanse or Lemon Detox.

Beyonce told GMTV: 'I would not recommend it if someone wasn't doing a movie, because there are other ways to lose weight.

'But I need to lose it really quick, and I put the weight back on as soon as I finished, so I am no smaller or bigger than I've always been.'

Demi Moore

The actress developed abs of steel and even shaved her head to play the first female Navy SEAL in the film GI Jane.

Since then she's adopted a much more slender, feminine look. Could it be the saying 'you're only as young as the man that you feel' is true?

Having said that, those surgery rumours just won't go away...

Christian Bale

The actor lost around 60 pounds to play the emaciated lead in The Machinist. He choose the role partly as a reaction to playing Patrick Bateman.

Christian said: 'I'd done American Psycho, and I bulked up purely for that part, but people start just going 'oh yeah, that guy's a real workout fanatic' and that's not me, that's Patrick Bateman. It was a nice way to kill that dead by just destroying your body completely.'

Christian then buffed up again using KFM (Keysi Fighting Method) to play Bruce Wayne in Batman Begins.

Brad Pitt

Brad has confessed he likes nothing better than sitting on the porch with his dog, but he's clearly no slacker when the role demands it if the pumped-up look he adopted for his roles in Fight Club, Snatch and Troy are anything to go by.

Jared Leto

The former squeeze of Cameron Diaz gained 62 pounds for his role playing Mark David Chapman in Chapter 27, but he's no stranger to fitting his diet into his work.

To play a heroin addict in Requiem for a Dream he lost 28 pounds.

Angelina Jolie

Tomb Raider saw Angelina put some meat on her bones with boxing, bungee ballet, kick boxing and yoga, but since then she's adopted a very frail look which meant her outfits kept having to be taken in for her latest film, Salt.

Jessica Simpson

Jess put in gruelling two-hour daily workouts to get her body in shape for Dukes of Hazard and has since faced a barage of criticism for her yo-yo-ing weight.

Daniel Craig

The man with the baby blue eyes wasn't really on our radar until James Bond, when he burst onto the scene with rippling muscles.

Renee Zellweger

The choice of skinny Renee to play voluptuous Bridget Jones raised eyebrows, but she threw herself into the role and dutifully gained the weight, lost it again, gained the weight and lost it again for Bridget Jones's Diary and Bridget Jones: The Edge of Reason.

If the rumours are to be believed, she's said to be preparing to reprise the role in the third installment. Watch out for a ballooning then shrinking starlett.