Jake Gyllenhaal drove himself "insane with hunger" while filming 'Nightcrawler'.
The 34-year-old actor's co-star Riz Ahmed, who played Rick Carey, the sidekick to the Hollywood hunk's sociopathic news reporter Lou Bloom in the crime thriller, joked he thought the hunk wanted to eat him while shooting the movie because he was so hungry after living off a diet of chewing gum to lose 30lbs for the role.
He said: "Jake lost a lot of weight for the role, he was literally surviving off chewing gum and driving himself with hunger, which makes sense because his character is desperately hungry for success.
"He's looking at me in the film like he might want to eat me.
"There was this primal energy coming off him."
Despite growing concerned that Jake might develop some cannibalistic tendencies, the 32-year-old star found the 'Brokeback Mountain' actor "really inspiring" to star alongside in the motion picture.
He added to Metro newspaper: "He was really inspiring. He's someone who really pushes himself to limits."
As well as chewing gum, Jake also lived on kale salad while thinning down for 'Nightcrawler' and ran 15 miles a day to and from his Hollywood home to the film set.
He recently said: "I made a lot of choices physically.
"The running thing, you're pretty hungry because you're not eating a lot of food.
"You're lonely because you're not meeting your friends for dinner. People go, 'Hey you want to meet for dinner after work?' I go, 'Well, I'm shooting all night.' 'All right, you want to meet for lunch?' I'm like, 'I can't!' So I'm gonna go run."