Imagine being asked to record an audition to play rock ’n’ roll legend Freddie Mercury in a movie, but your tryout is specifically for the members of Queen, Mercury’s former bandmates. That was the awkward position Rami Malek was put in before he starred in the Mercury biopic “Bohemian Rhapsody.”

“We ended up watching it [together] in Roger Taylor’s flat, in London,” Malek says. “One of the craziest, most surreal moments of my life, was standing next to them and basically trying to gauge their reaction in real time. Something no human should be subject to.”

Malek, best-known for his Emmy-winning role on “Mr. Robot,” has spent most of his free time in serious roles in indie films such as “Short Term 12” and “Buster’s Mal Heart.” Playing Mercury in a movie that comes awfully close to a musical was completely out of his comfort zone.

“I don’t know what gave him the idea that the guy playing a profoundly alienated computer hacker with debilitating social anxiety would be the perfect candidate for Freddie Mercury,” he jokes.

Oh, and that tape wasn’t all Malek had to do to land the role. He recorded another at Abbey Road Studios where he sang four songs as well as a Q&A with screenwriter Anthony McCarten and executive producer Denis O’Sullivan in which he “instinctually” responded in his own version of Freddie.

“I put everything I had into that for two weeks to prepare,” Malek says. “I ate, slept, breathed everything Freddie Mercury, which then I continued to do for the next year almost.”

That all led up to arguably the biggest moment in the film, a re-creation of Queen’s set at the 1986 Live Aid concert. In Malek’s eyes, he needed to know where Mercury’s movements came from to pull it off. That meant studying everything from boxing (Mercury was a boxer as a young kid) to Liza Minnelli, one of Mercury’s idols.

“I would try to understand his mannerisms with the help of a movement coach named Polly Bennett,” Malek says. “We would sometimes go and use a rehearsal space to perform ‘Killer Queen.’ She’d go, ‘Now, why don’t you give me a soliloquy of “Killer Queen” in the style of Marie Antoinette.’”

Malek isn’t the only actor to attempt something unexpected. In Peter Farrelly’s “Green Book,” Viggo Mortensen plays Tony Lip (born Frank Anthony Vallelonga), a real-life Brooklyn bouncer who in the early 1960s was hired to drive and protect famous classical pianist Don Shirley (Mahershala Ali) on a tour of racially segregated cities in the South. Not only is this the first time Mortensen has portrayed anyone with a specific New York City dialect, but it also features the most comedic work of his entire career. When Mortensen got the script he was immediately impressed and also afraid he might not be the right man for the job.

“Each time I read it I liked it more, but it also made me nervous,” Mortensen says. “I felt not only a responsibility to the Vallelonga family, but I’m aware of some very good actors who are Italian-American [were out there and] some memorable characters on TV and in movies in recent decades that are Italian-American. So, the last thing I want to do is mess up the movie and just do a caricature in it.”

Nick Vallelonga, Tony’s son, is a co-screenwriter of the film and was a wealth of information as Mortensen researched his role. Vallelonga also introduced him to the rest of the family and that, the two-time Oscar nominee says, was the foundation of his portrayal. They also shared recordings of Lip that were helpful in “just hearing his rhythms of speech.” There was also video of Lip on screen in his later years thanks to the small parts he landed as an actor.

“No matter what the movie was, there was something that he always did,” Mortensen says. “He had something that many veteran actors would like to have, which is an ability to relax. I don’t know, a self-confidence and a relaxation that gave him a lot of power when he was being filmed. The way he listened to other actors, he was really present, he just had that naturally, obviously. “

Steven Yeun is best-known for his role in “The Walking Dead,” but since leaving the AMC hit he’s branched out into fare such as Boots Riley’s “Sorry to Bother You” and Bong Joon-ho’s “Okja.” When he was offered the role of Ben in Lee Chang-dong’s dramatic thriller “Burning,” he admits he was initially “kind of in shock.”

“I thought he was gonna offer me just [a role] to play an expat. Someone to come in and speak some English and then leave or do something to that extent,” Yeun says. “But, then when I read the short story I realized who he wanted me to play. When I got the script I was so excited, but before I even met him I was mentally preparing myself to maybe say that I couldn’t do it. I revere the man so much that I didn’t want to really be a stain on his filmography. Not from an acting standpoint, but if you want a Korean actor? I’m a Korean-American actor and that’s very different.”

The celebrated auteur eventually persuaded Yeun he knew what he was getting into and it didn’t hurt that he also happens to be a linguistics professor.

“My Korean is decent, and pronunciation is good, but the nuance that a full, native Korean embodies and carries with them in the way that they talk and their intonation is very specific. So, we did a lot of work.”

“Burning” ends in an extended one-shot featuring Yeun’s character and the film’s protagonist, Lee, played by Yoo Ah-in. The sequence was shot after most of the principal photography had ended with Yeun returning to the U.S. in the interim.

“That one was actually pretty crazy,” Yeun says. “We shot that last scene in one day. That was the only day that it ever snowed, so that snow-covered day was perfect for it. We got three takes and there was just this natural finish. We didn’t overly practice.”

There are a number of other actors this year who took on roles that were something of a surprise including Bradley Cooper in “A Star Is Born,” John David Washington in “BlacKkKlansman,” Hugh Grant in “Paddington 2,” Nicholas Hoult in “The Favourite” and John C. Reilly in “The Sisters Brothers.”

An Oscar-nominee for his performance in “Chicago,” Reilly’s role in “Brothers” required him to learn how to shoot a gun and ride a horse for the first time in his career. In fact, Reilly and the film’s director Jacques Audiard thought of Patrick deWitt’s novel more as a period piece.

“It’s really hard to predict what’s going to come your way as an actor, but I will say this: I try to do everything that I can do,” Reilly says. “That’s one of the great things about my career is some people get known for one thing and I get known for doing something different almost every time, and that makes for a really exciting, gratifying life, I have to say. So, no, I didn’t set out to find a Western or to make a Western, but this Western just came to me.”