Jared Leto gorged on melted Haagen Dazs ice-cream, laced with olive oil and soy sauce to bulk up to play John Lennon's killer Mark David Chapman in new movie CHAPTER 27.
The actor ballooned on the diet and stunned castmates including Lindsay Lohan with his massive weight gain.
He says, "(I did it) eating everything you think you're not supposed to - pizza pasta,
ice-cream, but my little trick was I would take pints of chocolate Haagen Dazs and put them in the microwave and drink them. The sick thing is I would actually pour olive oil and soy sauce into the mixture as well - to get me bloated even more."
Leto embarked on an equally bizarre seven-week diet to lose the weight he piled on.
He explains, "I've been fasting ever since. I've been doing this very strange, like, lemon and cayenne pepper and
water fast. I didn't eat any food for 10 days straight; I think I lost 20 pounds that first 10 days."