stars go to great lengths to make their performances realistic. Have a look at
Jim Carrey's performance as Andy Kaufman in their new Netflix documentary.
Gary Oldman is no different. He's not quite as manic and obsessive as Jim Carrey, but there is a good reason that he is one of the world's best.
In his latest film, Darkest Hour, he takes on his most difficult role yet - Winston Churchill.
To start with, the two men look nothing alike. Churchill weighed significantly more than Oldman does. Working around this meant creating a huge, yet incredibly lifelike bodysuit for him to wear.
The whole thing added about six-and-a-half kilos of weight to Oldman's costume, and took so long to get in and out of that during the course of the whole shoot he was averaging 17-hour days.
Talk about suffering for your art, right? That's not even the worst of it.
When we think of Winston Churchill, we think of the bullish wartime prime minister who was hard talking, hard drinking and, of course, hard smoking.
This meant that throughout shooting Oldman had to be seen with a huge Cuban cigar permanently hanging from his mouth.
Now, even if he were a heavy smoker, the task of having to smoke cigars all day would still be tough.
And they certainly went through them. They reckon he smoked around 400 Romeo Y Julieta Cubans over the course of the filming, which, at $50 (£37) a go, meant that they eventually spent $20,000 (£15,000) on cigars alone.
As well as spending more than most average people earn in a year up on smoke, their quest for authenticity also took quite a toll on Oldman's health.
He told The Hollywood Reporter: "I got serious nicotine poisoning. You'd have a cigar that was three-quarters smoked and you'd light it up, and then over the course of a couple of takes, it would go down, and then the prop man would replenish me with a new cigar - we were doing that for 10 or 12 takes a scene."
That's some dedication to the craft right there. Putting your own health at risk might seem silly, but, as director Joe Wright also told THR: "You can't have Winston Churchill without a cigar."
The risk appears to have paid off, with critics already praising Oldman's performance as Churchill. The film is tipped for quite a few of the big awards this year.
They'll be hoping they don't get close, but no cigar. I'll get my coat.
Featured Image Credit: Darkest Hour / Universal