“Saturday Night”'s Lamorne Morris explains Garrett Morris' climactic (and improvised!) 'Kill All the Whities' song

"The band immediately played it, and now the onus is on me to keep up. And I'm like, 'No, no, Jason, slow down. These are professionals! You got to hold on!'"

Warning: This article contains spoilers for Saturday Night.

When Lamorne Morris arrived on set for his climactic scene in Saturday Night, he knew he'd be singing a little. He ended up singing a lot.

In Jason Reitman's Saturday Night Live biopic, the New Girl star plays Garrett Morris, the first Black performer to join the SNL cast. Over the course of the film, Garrett struggles to find his place on the show — he's a Juilliard-trained thespian who's over a decade older than his castmates, and the all-white writers' room didn't immediately know how to appropriately accommodate a performer of color.

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After confiding in the similarly aimless Jane Curtin (Kim Matula) and palling around with musical guest Billy Preston (Jon Batiste) and his band, Garrett finally gets his chance to shine during soundcheck, just minutes before SNL goes live for the first time ever. In the film's most triumphant sequence, Garrett sings a hilarious, provocative song with the refrain "I'm gonna get me a shotgun and kill all the whities I see," accompanied by Preston's instrumentalists.

Though the tune doesn't appear in SNL's inaugural broadcast, the real Garrett Morris did perform the song on a later episode of the season. "Garrett told me that that song was the moment he realized, 'Okay, I know what I'm doing here. I know what my objective is. I get to bring all of my skill set here,'" Lamorne Morris tells Entertainment Weekly. "It's not traditional, and it's groundbreaking for NBC to air something like that. It's nuts! And I'm so very grateful to folks like him who've done things like that to pave the way for entertainers to be able to break the mold a little bit, to push the envelope and to throw caution to the wind when it's time to truly express creativity."

Morris (who has no relation to the comedian he plays in the movie) trained with a vocal coach to prepare for his big moment — but the extensiveness of the musical number wasn't decided until shooting began. "The craziest part is that originally it wasn't that long of a song," the actor says. "It was just supposed to be a couple of bars of it. And then we have Jon Batiste's band there, who are all very magical musicians — the things they know how to do, they're all actual musical prodigies."

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The musical talent on set inspired experimentation. "So Jason said, 'Oh, I want to keep the song going a little longer — let's vamp, then let's do this, this, and this," Morris recalls. "And then the band immediately played it, and now the onus is on me to keep up. And I'm like, 'No, no, Jason, slow down. These are professionals! You got to hold on!'"

The recent Emmy winner was able to keep pace with the band, but it was still a terrifying experience. "That was a very frightening day for me because I didn't know how it was going to be received," he says. But I'm grateful that this cast was a very tight group. We all cheered each other on, and so you had everybody there just watching."

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Andrew Barth Feldman, who performed in Dear Evan Hansen on Broadway and played opposite Jennifer Lawrence in No Hard Feelings last year, provided a key suggestion for Morris. "On that last note where I say, 'Get me a shotgun and kill on the whities I see,'" Morris starts, crooning the last line and jumping into a piercing falsetto on the final word. "That's not how Garrett actually did it, but Andrew was like, 'Hey, you should try it like this.' And he's a professional singer. His voice is insane. So he did it and I was like, 'Holy s---, I'm going to try it.' So I went back and said 'I need one more take. I just need one more take.' And then I did it, and then that's what Jason ended up using."

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Morris recorded his vocals live on set that day, and joked that he wished he had considerably more time to rehearse. "It was no ADR, no studio stuff," he says. "When Jason said he wanted it to be a longer moment, I was just like, oh, 'We're going to try this? Can I call my vocal coach? I got to go back to L.A. and workshop this. Give me a second — give me eight days, Jason, I'll be right back.' But yeah, it seemed to work out. Jason trusted us to just be loose and we trusted that he was going to handle the rest, and that's what he did."

Related: Meet the SNL biopic cast: See Saturday Night stars next to real Lorne Michaels, Chevy Chase, George Carlin, more

Saturday Night is now playing in theaters.

Read the original article on Entertainment Weekly.