Hollywood's most astonishing movie transformations

Hollywood is full of chameleons. It's the land of make-believe, after all.

Actors and actresses love to switch up their looks, not only on the red carpet but on the big screen.

From donning heavy prosthetics to dramatically downsizing on draconian diets, many stars have completely transformed for their unforgettable roles. 

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When transformations come to mind, it's hard to go past Christian Bale, who has famously yo-yo dieted to play diverse characters.

His extreme body transformation in 2004 for The Machinist saw the star drop 27 kilograms on a diet of whiskey and cigarettes. Definitely not recommended.

And then for the 2018 flick Vice, Bale stacked it all back on again – and then some – as he prepared to play US Vice President Dick Cheney. Needless to say, the actor has admitted in a previous interview that it's more fun "gaining the weight than losing it".

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Joaquin Phoenix's look is just as versatile. His haunting portrayal of The Joker saw him shed 23kg but gain a Best Actor Oscar. The actor is no stranger to transforming for a role, but he always does it under the watchful eye of a professional. 

"It's something I've done before and you work with a doctor regimented and overseen and safe," Phoenix said in the past. 

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When it comes to damsels in disguise, Charlize Theron is a serial offender. For her Oscar-winning performance in Monster, the stunning star gained around 13 kilograms and changed the appearance of her face to portray serial killer Aileen Wuornos. 

Theron again spent hours in the makeup chair for her role as Fox News presenter Megyn Kelly in the 2019 drama Bombshell, which was based on real-life events. 

Watch the video above, presented by Today Extra entertainment reporter Britt Cohen, to see the biggest transformations in Hollywood.