There is dedication and then there is dedication that defies the limits of human endurance. When an iconic role comes along, there is a huge competition among actors and expectations are raised above the bar. Some actors want to impress, while others believe there is no other way to go about it than to plunge themselves deep into the character, even if it’s as deep as an abyss.

It’s the satisfaction they get when they know they have given everything they possibly could, or previously thought couldn’t, that drives them. Here are some facts about famous actors who were just that dedicated to their roles and never once flinched about it.

1 For his role in The Machinist (2004), Christian Bale went on a daily diet of one can of tuna fish or an apple, black coffee and water.

Christian Bale plays an insomniac who experiences physical and psychological deterioration because of the lack of sleep. To get the right appearance for the role he lost almost 62 pounds (28 kg) by taking very low calorie food and underwent vigorous exercising to speed it up. It’s also reported that he smoked cigarettes, ate salads and chewed gum for the role. What’s more, after the filming is done he had to rapidly gain weight and muscle in just six months for his role as Bruce Wayne in Batman Begins.(source)

2 Shia LaBeouf joined the US National Guard, had a cross tattooed, became a chaplain’s assistant, spent a month living in a forward operating base, pulled his tooth out, knifed his face and spent days watching horses die to prepare for his role in Fury (2014).

From being a child artist in Disney Channel to being a critically acclaimed actor, Shia LaBeouf has come a long way. According to an interview, when the movie’s director told his cast to give all they’ve got Shia LaBeouf had no reservations to how much he wanted to give. Needless to say he received much praise for his role in the movie.(source)

3 Tom Cruise worked as a delivery man delivering packages without being recognized to prepare for the role of Vincent, a contract killer who has to move unnoticed in a crowd, in the movie Collateral (2004).

The movie Collateral features Tom Cruise as a contract killer who hires a cabbie for the whole evening while he carries out his kills. Apart from Tom Cruise practicing staying anonymous in a crowd, Jamie Foxx trained as a cab driver to prepare for his role as the cabbie. They were both even given documents by the director Michael Mann containing the characters’ backgrounds for better portrayal in the movie. There is also a cameo appearance of Jason Statham who delivers a bag to Tom Cruise and then disappears.(source)

4 Leonardo DiCaprio, who plays Hugh Glass, lived in the harshest possible climates, slept in animal carcasses and ate raw bison liver to prepare for his role in The Revenant (2015).

The Mexican director Alejandro González Iñárritu was very particular about filming the film perfectly which led to the cast and crew having to travel far to remote locations with -25⁰ centigrade just to film for 90 minutes. Leonardo DiCaprio perhaps had it worse than all the others. He even had to plunge in and out of freezing river water for the movie.

In an interview given to The Hollywood Reporter, the director said the movie would have been nothing if they sat comfortably drinking coffee and using green screens to film the scenes instead of actual locations.(source)

5 For the movie My Left Foot (1989), Daniel Day-Lewis as good as lived on the wheelchair during the filming to stay in character. The slumped posture that he adopted for his character gave him two broken ribs.

Daniel Day-Lewis is known for going to extremes to prepare for his role. My Left Foot, in which he plays Christy Brown, an Irish writer and painter suffering from cerebral palsy, is only one such movie. For his role in In the Name of the Father he lost 30 pounds and lived on prison rations. He also spent a lot of time in the set’s cell and was interrogated by real police for three days. He didn’t stop there, he asked the crew members to throw abuses and cold water at him as well.(source)

6 Heath Ledger spent about a month locked up in a hotel room to prepare for his role as the Joker in The Dark Knight (2008).

In a German documentary called Too Young To Die, Heath Ledger’s father shared how dedicated he was about acting. Heath Ledger kept a diary full of notes about his character the Joker for the movie. There is also a page in his diary where he writes about the hospital scene. According to father, when he was a kid his sister would make him play the nurse by getting him dressed for the part. The role also took a psychological toll on him as he delved deep into the sociopathic mind of his character.(source)