Phoenix has said he was driven mad by the intense weight loss required to embody the skeletal Arthur Fleck in Joker. (Credit: Lev Radin/Pacific Press/LightRocket via Getty Images/Warner Bros) (Yahoo Movies UK)
2/19
Bill Skarsgård in 'It: Chapter Two'
The creepiest of the Skarsgård clan terrified audiences all over again under layers of make-up as Pennywise the Dancing Clown in It: Chapter Two. (Credit: Debra L Rothenberg/Getty Images/Warner Bros) (Yahoo Movies UK)
3/19
Margot Robbie in 'Mary Queen of Scots'
The Once Upon a Time in Hollywood star transformed into the white-faced Queen Elizabeth I in Mary Queen of Scots. (Credit: Axelle/Bauer-Griffin/FilmMagic/Universal) (Yahoo Movies UK)
4/19
Kenneth Branagh in 'All Is True'
One of the UK's greatest thespians, complete with bald cap and enormous fake schnozz, portrayed the final years of William Shakespeare in All is True. He's also the director, so he has no one else to blame. (Credit: Leon Bennett/Getty Images/Sony) (Yahoo Movies UK)
5/19
Christian Bale in 'Vice'
Bale is no stranger to transformations and was totally unrecognisable as the devious Vice President Dick Cheney in awards season biopic Vice. (Credit: Araya Diaz/Getty Images/eOne) (Yahoo Movies UK)
6/19
Taron Egerton in 'Rocketman'
Egerton plays Elton John throughout several decades of his life in Rocketman, sampling many of the star's most outlandish looks. (Credit: Steve Granitz/WireImage/Paramount) (Yahoo Movies UK)
7/19
Shia LaBeouf in 'Honey Boy'
LaBeouf sports a balding wig and enormous glasses to embody a version of his own father in the bracing drama Honey Boy. He wrote it too. (Credit: Rachel Luna/FilmMagic/Sony) (Yahoo Movies UK)
8/19
Nicole Kidman in 'Destroyer'
Nicole Kidman infamously wore a large prosthetic nose for The Hours, but her transformation into a weary LA cop in Destroyer was even more dramatic. (Credit: Taylor Hill/Getty Images/Lionsgate) (Yahoo Movies UK)
9/19
Robert Carlyle in 'Yesterday'
Everyone involved is being very hush-hush about it, but the actor who pops up as John Lennon in the Beatles musical Yesterday is regular Danny Boyle collaborator Robert Carlyle. (Credit: Isabel Infantes/PA Images/Universal) (Yahoo Movies UK)
10/19
Ben Mendelsohn in 'Captain Marvel'
In order to create Skrull leader Talos in Captain Marvel, Aussie actor Mendelsohn had to spend several hours in the make-up chair every day. (Credit: Ian West/PA Images/Marvel) (Yahoo Movies UK)
11/19
David Harbour in 'Hellboy'
Stranger Things actor David Harbour got bulkier, redder and hornier to play the demonic antihero in the rather ill-fated Hellboy reboot. (Credit: Jason Mendez/Getty Images/Lionsgate) (Yahoo Movies UK)
12/19
Robert De Niro in 'The Irishman'
There are roughly 60 years of De Niro in The Irishman, from a youthful 20-something soldier to an octogenarian in a nursing home, all achieved through some very impressive digital de-aging work. (Credit: Albert L. Ortega/Getty Images/Netflix) (Yahoo Movies UK)
13/19
Renée Zellweger in 'Judy'
The former Bridget Jones transformed herself into Hollywood icon Judy Garland for the biopic Judy. She'll be hoping to find an Oscar somewhere over the rainbow. (Credit: Steve Granitz/WireImage/Pathe) (Yahoo Movies UK)
14/19
John C. Reilly in 'Stan & Ollie'
Reilly spent four hours in the make-up chair and worse a large bodysuit to portray legendary comedian Oliver Hardy in biopic Stan & Ollie. (Credit: George Pimentel/WireImage/eOne) (Yahoo Movies UK)
15/19
Matthew McConaughey in 'The Beach Bum'
In case you can't tell, this is what a stoner poet called Moondog looks like. (Credit: Rick Kern/Getty Images/Blue Finch Films)
16/19
Zac Efron in 'The Beach Bum'
Harmony Korine's stoner comedy also gave the world this Zac Efron look. It's probably a good thing no one saw it. (Credit: Steve Granitz/WireImage/Blue Finch Films)
17/19
Charlize Theron in 'Bombshell'
More than a decade after completing one of the most ambitious transformations ever for Monster, Theron has changed herself completely once again for Fox News real-life drama Bombshell. (Credit: Tibrina Hobson/WireImage/Lionsgate) (Yahoo Movies UK)
18/19
Jamie Bell in 'Skin'
As a former neo-Nazi dealing with the lasting impact of his past beliefs, Bell had to sport an entire face's worth of tattoos. He's a long way from Billy Elliot now. (Credit: Morgan Lieberman/WireImage/Lionsgate) (Yahoo Movies UK)
19/19
Every Single Actor in 'Cats'
The horror, the horror. The absolute horror of all of this. People like cats, but human-cat hybrids with the face of James Corden are a different kettle of (cat)fish entirely. (Credit: Peter Barreras/Invision/AP/Universal) (Yahoo Movies UK)
Physical transformation is a huge part of the actor’s toolkit, whether it’s gaining weight, adopting a new physicality or sitting in the make-up chair for hours on end while talented crew members work their magic.
This year has yielded an unusual array of transformative performances, with many of the world’s most famous faces changed beyond all recognition in service of delivering something special on the big screen.
From glossy awards season biopics to mega-budget blockbuster spectaculars, the craft of an actor often requires a willingness to take risks in delivering a memorable look.