Chris Hemsworth was weak on set of In the Heart of the Sea

Chris Hemsworth (c) Instagram

Chris Hemsworth has admitted he thought he was going to "pass out" when he was filming for 'In the Heart of the Sea' because of the lack of food

Chris Hemsworth felt like he was going to "pass out" when he was shooting his new movie 'In the Heart of the Sea.'

The 31-year-old actor was forced to follow an extremely low-calorie diet for his role as shipwrecked sailor Owen Chase in the sea-set drama and has admitted the consequences of starving himself left him feeling light-headed and unwell.

Speaking on Australia's 'Kyle and Jackie O Show,' he said: "We felt as if we were going to pass out any second."

The handsome star - who is known for his bulging biceps and ripped abs, especially when playing superhero Thor - called on Tom Hanks to ask him for some advice on how to drop the weight following his role in 2000's 'Cast Away.'

He explained: "We called up Tom Hanks and he gave us some advice on how to lose the weight."

Jackie 'O' Henderson asked: "So, what is the trick?"

Hemsworth replied: "Don't eat. Pretty straight-forward."

The hunk lost 33lbs by the end of filming and he believes the starvation he experienced helped him get into character.

Jackie said: "When you're that food deprived and cranky, does it help with doing a film where you're essentially lost at sea and you wouldn't be in the best of moods?"

Hemsworth hit back: "It does. Looking back, it was essential to doing the story justice. It was based on true events which inspired Moby Dick to be written. There wasn't a lot of acting required for those last couple of weeks."

Meanwhile, earlier this week, Hemsworth uploaded a photograph of his shrunken figure on his Instagram account.

'In the Heart of the Sea' - directed by Ron Howard and based on a true event that happened in 1820 - is set for release across the US on December 11.