Acting isn’t known as a particularly down-and-dirty profession. More often than not, in fact,… Acting isn’t known as a particularly down-and-dirty profession. More often than not, in fact, movie stars cultivate an image of effortless refinement. Thankfully, men like Mickey Rourke are reaffirming that being a true thespian is grueling — even perilous.

According to Sunday’s Wales, a Welsh newspaper, Rourke (“The Wrestler,” “Iron Man 2”) wants to have his two front teeth removed in preparation for his role as Gareth Thomas, an openly gay rugby player who lost his top incisors.

Put curtly by Thomas’ agent, “Mickey intends to get as close to the character as he can, as he thinks it is a great story.”

To say this sort of transformation is unnecessary — isn’t that what makeup is for? — is to overlook a long-established Hollywood tradition. It is a tradition that values results over safety, mettle over intelligence — method acting.

Simply put, method acting is an attempt at character immersion in the most all-encompassing sense — a means of inhabiting one’s role to the point where the role supplants the actor. To truly “know” a character, method actors believe, it’s necessary to live, breath, behave and, eventually, think as that character would.

This is a fascinating, albeit hazardous, approach to the craft — one too often underappreciated by audiences and critics. To remedy this, I’ve compiled a list of a few renowned method actors, and their precarious forays into the minds of their subjects.

Christian Bale: The now-ubiquitous Mr. Bale (“The Dark Knight,” “Terminator Salvation”) takes his work very seriously — too seriously, in fact. Years before he hurled abuses at the “Terminator” director of photography for walking into the frame and breaking his concentration, the Welsh actor pursued his role as the sleep-deprived, horrifically thin Trevor Reznik in “The Machinist” (2004) with the same frightening zeal.

In accordance with Reznik’s habit of spurning anything but the smallest morsel of food, Bale confined his daily diet to a cup of coffee and an apple. Soon, he had lost 63 pounds, rendering himself an emaciated caricature of his formerly robust figure — a transformation he replicated to a lesser extent in the recent film “The Fighter.”

Robert De Niro: De Niro’s transformation for “Raging Bull” (1980) was in some ways the antithesis of Bale’s — the actor gained, rather than lost, about 60 pounds — but he abided by the same principle: understanding characters on their own terms.

To more believably inhabit the role of middleweight champion Jake La Motta, De Niro engaged in a rigorous training regiment, sparring some 1,000 rounds with La Motta himself and, according to Vanity Fair, La Motta suffered chipped teeth, black eyes and a broken rib, courtesy of De Niro. Thankfully, the hard work paid off: In addition to netting an Oscar for his performance, the actor engaged in three professional bouts and won two of them.

Of course, De Niro’s physical conditioning wasn’t limited to one film — the actor ground his teeth to portray the degenerate Max Cady in “Cape Fear” — but “Raging Bull” is still cited as a pinnacle of method acting and film in general.

Daniel Day-Lewis: He established himself in 1989 with “My Left Foot” — when, to more adequately understand the cerebral-palsy-stricken writer he was playing, Lewis asked to be carted to and fro in a wheelchair and fed with a spoon. The British recluse, often considered the world’s premier method actor — though he himself shuns the title — has set the bar so high that it’s almost impossible to top him and survive.

Perhaps the most impressive of his stunts occurred during the shooting of the 1993 film “In the Name of the Father,” about a man wrongfully convicted of committing an Irish Republican Army bombing and subsequently sent to prison. In preparation for conveying the ordeal, Lewis confined himself to a frigid cell for three nights and asked that those on the set, according to the London Evening Standard, “abuse him” and hurl water on him.

As if this wasn’t sufficient psychological stress, Lewis would spend entire days working himself into a frenzy if a scene called for rage. As one technician put it, “He would start getting really angry a few days beforehand and would be glaring and snarling at people on the set … You had to know when to steer clear of him because he could be pretty terrifying when he was in character.”