Meet Alden Ehrenreich, of the Coen brothers’ ‘Hail, Caesar!’

It’s not easy pretending to be a bad actor. In the Coen brothers’ “Hail, Caesar!” Alden Ehrenreich has to do just that. He plays Hobie Doyle,a fictitious star of singing cowboy pictures in early ’50s Hollywood, and the studio bosses decides he should try his hand at light comedy. What’s bad for the film-within-the-film is great for the audience, as Ehrenreich nails the deer-in-headlights awkwardness of a limited thespian who’s been miscast.

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In truth he’s never felt uncomfortable performing on screen.

“I started acting when I was really young,” Ehrenreich tells us. “I was 18 in my first movie. When you’re that young you don’t know any better. You don’t know that you should be uncomfortable.”

The Coens are famous for not giving their actors a lot of notes yet still getting highly stylized, precise performances. How can you tell you’re doing what they want?

“Well, if they’re laughing, that’s one thing,” Ehrenreich says. “They laugh out loud during takes to the point where sometimes you have to re-record stuff. If they’re liking something they just laugh, which makes it really fun cause you feel like you have a real audience there.”

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Ehrenreich, 26, is no stranger to the film classics. “When I was really little, my parents used to do these film festivals in our house, where we’d watch like every Charlie Chaplin movie or Marx Brothers movies or Westerns. A lot of Westerns.” That came in handy for “Caesar!” in which he has to rock the stiff acting and light crooning that came with America’s then-most popular film genre.

The Coens are far from the first major filmmakers for whom Ehrenreich has worked. He got his breakthrough acting with Vincent Gallo in 2009’s “Tetro,” for no less than Francis Ford Coppola, who cast him again in his 2011 3-D film “Twixt.” He had a small role in Woody Allen’s “Blue Jasmine,” and this year should see the release of Warren Beatty’s still untitled Howard Hughes movie, in which he’s second-billed. On top of that, he was discovered as a teen by Steven Spielberg, who saw a comedic video he acted in for a friend’s bar mitzvah.

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All of this came in handy for “Hail, Caesar!”, which requires knowing a lot about Golden Age Hollywood.

“The best research for old Hollywood research is Warren,” he says. “Warren came here in 1959 and has been famous for 50 years. He knew Orson Welles and knew Charlie Chaplin and knew [MGM boss] Louis B. Mayer and knew [producer] Charlie Feldman and [writer] Lillian Hellman and all these people. I met with Warren for about five years before we made the movie and that time was spent getting all this history from him and hearing these incredible stories.”