Joaquin Phoenix lived on "lettuce, asparagus and apples" to slim down for 'Joker'.
Joaquin Phoenix
The Oscar-winning actor previously revealed he'd lost over 50lbs for his lead role in the movie and has admitted he undertook a "horrible diet" involving just one very limited meal a day.
He told Total Film magazine: "It was a horrible diet. In May, I started eating super-clean. Like, just salads, very little dressing. Steamed vegetables, right?
"And then I'm working out. That got me down to a certain weight.
"And then I went on the really hardcore diet, which is lettuce and either steamed green beans or steamed asparagus and one apple. And you do that once a day."
Although Leonardo DiCaprio was initially linked to the DC Comics origins tale, director Todd Phillips insisted it was always written with Joaquin in mind.
He said: "I don't know how things get started. I'm being honest. Maybe it's because Leo could be in any movie because he's Leo and he would fit in any movie because he's one of the greats of all time?
"But we wrote this script for Joaquin. It's true. Joaquin knows it.
"Half the reason we wanted to even attempt writing it was, 'Man, imagine if we get Joaquin. Think of what we can do.'
"The goal was never to introduce Joaquin Phoenix into the comic-book movie universe. The goal was to introduce comic-book movies into the Joaquin Phoenix universe."
Joaquin recently admitted losing so much weight had made him start to "go mad".
He said: "The first thing for us was the weight loss.
"I think that's really what I started with. And, as it turns out, that then affects your psychology. You start to go mad when you lose that amount of weight in that amount of time."
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