Hollywood has always been drawn to true stories and there will never be a shortage of actors needed to re-create famous lives. But when portraying a real person who is dead or is even still alive, actors have their work cut out for them. On the one hand, they usually have lots of material to draw from. On the other, they don’t want their performance to be mere mimicry.

“Playing real people is interesting, and I’ve played many,” says Gary Oldman, nominated for his starring role in “Mank” as “Citizen Kane” screenwriter Herman Mankiewicz. Oldman previously won an Academy Award for playing Winston Churchill in “Darkest Hour” and his film career was launched in 1986 when he starred in “Sid and Nancy” as Sid Vicious.

“A lot of the work is done for you. There’s usually first-hand description, personal writings and a ton of written material about the individual. The back story is filled in for you. With a fictional character that’s the stuff you’re making up. There are, invariably, people living — friends or family members, so you do feel a responsibility to them. You try and honor the memory. I am told the Mankiewicz family were happy with my interpretation. That can often mean more than any critical acclaim.”

Oldman admits he didn’t know much about the man himself. “I only knew of Herman’s association with ‘Citizen Kane.’ I was more familiar with his famous brother, Joe — film director, producer and screenwriter.”

But he wasn’t terribly concerned with capturing Mankiewicz’s physical appearance — especially as he wasn’t someone instantly recognizable. “The look, so to speak, was less important. There’s a spirit or essence of the person you want to capture.”

To prepare, he turned to the biography “Mank” by Richard Meryman and utilized footage of his brother Joe for vocal cadences. “I figured the proverbial apple wouldn’t have fallen far, so I studied Joe and used him as a springboard.”

Ultimately, Oldman says, “This is not to be confused with impersonation. It’s a pinch of inspiration that you can build on and make your own.”

When it came to portraying activist Abbie Hoffman in “The Trial of the Chicago 7,” Sacha Baron Cohen also found the voice and accent a vital part of the role. Cohen was familiar with Hoffman’s life, from when he did a thesis on Jews in the civil-rights movement back in his 20s. When Steven Spielberg was originally going to make “Chicago 7” more than 15 years ago, Cohen reached out about playing Hoffman — which, he says, “is a slightly cheeky thing to do.”

Spielberg admitted he was concerned about the British Cohen pulling off Hoffman’s accent. “It’s a really complex accent because he’s from Boston but then it’s got hints of Berkeley and Brandeis,” Cohen notes. “And his voice jumps an octave when he gets excited. The rhythm of it completely changes, depending on whether he’s giving a speech or he’s in private because he studied Lenny Bruce, the stand-up.”

Cohen listened to Hoffman’s voice and recorded a speech of his for Spielberg — he estimates he did about 20 takes and thought he was sending the best one, not realizing they were all sent. Still, Spielberg was impressed enough by the final result to cast Cohen. And though he dropped out of the project, when Aaron Sorkin came on board to direct, Cohen kept the role.

Cohen had only played one real person before — Mossad spy Eli Cohen in the limited series “The Spy” for Netflix. He admits such roles come with an extra responsibility. “I have an obligation because their family is still alive,” says Cohen. “And it was really rewarding to have Abbie’s nephew speak up and say that he felt he could see his uncle on screen.”

Leslie Odom Jr. was also familiar with Sam Cooke long before he played the singer in Regina King’s directorial debut, “One Night in Miami.”

“I can’t remember a time when Mr. Cooke wasn’t a part of my consciousness. He’s one of my most influential teachers and mentors from the beyond for most of my life.”

Odom’s no stranger to playing real-life figures: he won a Tony and Grammy Award for playing Aaron Burr in “Hamilton,” and also portrayed William Still in “Harriet.” But still he says there is some intimidation in playing a real person, particularly a legend such as Cooke. “It was the most terrifying part. Mr. Cooke means a lot, to this day, to many, many people. He is beloved.”

When it came to playing Cooke, Odom says, “I wanted to conjure him fully and completely if I was able. I desperately wanted to disappear.

“Thanks to the support on set, a brilliant director and co-conspirator in Regina, and tremendous scene partners, I think there were moments when the illusion came pretty close.”

Portraying a real person in tragic events take a toll on the actor. Daniel Kaluuya was excited to portray Black Panther Illinois party chairman Fred Hampton, who was killed by law enforcement in 1969, but also found “it was a tall order.”

“It was like a big mountain. When you get to the bottom of the mountain and go, ‘Whew, this is big. It’s even bigger than I thought it was from a distance.’ And so drop by drop, a river is formed. You just got to keep plugging away. It’s got to keep plugging away, show up every day, show up every day and then something will happen. So I just moved like that.”

Kaluuya says there were challenging moments — he was at a Q&A promoting “Queen & Slim” the night before he had to perform Hampton’s famous “I am a revolutionary” speech. “Queen & Slim” director Melina Matsoukas saw his face and could tell he was exhausted. “She was like, ‘I can’t believe you have that scene tomorrow,’” recalls Kaluuya. “I was like, ‘Yeah, it’s insane.’ But you put it in perspective. He came out of prison. What can I complain about? These people really lived this. So it’s kind of always keeping that in the front whilst you’re going through it and then when you finish it, you go actually do the work and heal.”