For a lot of actors, getting into the role can mean making some serious physical and psychological changes.
Some actors put on or lose weight, others develop accents and mannerisms to suit the role, and research is always a big part of it. For Holt McCallany, who plays Bill Tench in Netflix's 'Mindhunter', there's a bit more to it than just the haircut and the smoking - although that's a big part of it.
For McCallany, he actually made contact with the real-life Ed Kemper, also known as the Co-Ed Killer, when he was in research for the role. However, Kemper never wrote back to McCallany. In an interview with THR, McCallany also revealed that he had a meeting with Bobby Beausoleil, a former member of Charles Manson's "family" and currently serving life in jail for the murder of fellow Manson follower Gary Hinman.
The level of research McCallany puts into the role is just as scary, to say the least. He smokes real cigarettes in every scene, even though he doesn't actually smoke, and that he gained 15 pounds for the role. "Early on, I recognized that Bill is this chain-smoking, hard-drinking, middle-aged bureaucrat who's on the road 40 weeks a year, eats crappy food, and he just wouldn't have a beach boy body."
Speaking on Damon Herriman, the actor who played Charles Manson both in 'Once Upon A Time... In Hollywood', and in 'Mindhunter', McCallany was nothing if not effusive in his praise. "He's a superb actor, that kid... When he steps onto the set, he looks exactly like Manson, it's extraordinary."