Jason McDonald/Netflix
Bradley Cooper said he was "terrified" to portray the legendary composer-conductor Leonard Bernstein in the film "Maestro."
Specifically, he was afraid of filming a live scene in which he conducted the London Symphony Orchestra.
"I was recorded live, I had to conduct them," Cooper said at a panel after a special screening of the movie in New York. "And I spent six years learning how to conduct six minutes and 21 seconds of music."
The scene shows Bernstein conducting the London Symphony Orchestra in Mahler's Resurrection Symphony at Ely Cathedral in 1976. It's considered one of his most famous performances, and Cooper said that he was "so worried" about the scene "because we did it live."
To prepare, Cooper watched a raw take of Bernstein conducting the orchestra and worked with Yannick Nézet-Séguin, the director of the Metropolitan Opera.
He added that he was "absolutely terrified that if I hadn't done the work then I wouldn't be able to enjoy myself in these scenes."
Cooper produced, directed, and co-wrote the film, according to IndieWire. Fellow cast members Carey Mulligan and Matt Bomer also appeared on the panel, and it was moderated by Lin Manuel-Miranda.