Watch: Kumail Nanjiani reflects on his nerves for Eternals Bollywood scene
The movie introduces Nanjiani's superhero character Kingo as a star of Indian cinema, leading a complex dance sequence in his opening scene.
Having transformed himself physically to play a super-powered being, Nanjiani admitted to Yahoo that it was the dancing he struggled with most.
Read more: On set with Eternals in the UK
"That was the scene I was most nervous for. I trained the most out of anything for that scene," said the 43-year-old Silicon Valley star.
"I wanted to get it right," he added. "I knew that it was going to be me doing it. With the superhero fighting, there are stunt people and you do some, but those guys are very good.
"With this, it's just me and 51 professional dancers."
Read more: Bollywood remake of Rambo being discussed
Nanjiani's co-star Salma Hayek, who plays the Eternals' leader Ajak, said he "took it very seriously" and "wanted to honour his culture" with the performance.
As for those who hope that Nanjiani will parlay his new skills into taking on a musical, it's not worth holding your breath.
"That was it. That's the most you're gonna see," he said.
Eternals follows the titular race of super-beings as they are forced to emerge from hiding after hundreds of years due to the re-emergence of the Deviants — evil alien creatures from whom they are sworn to protect Earth.
Nomadland director and Oscar-winner Chloe Zhao is in the director's chair, overseeing one of the most diverse casts in the history of the Marvel Cinematic Universe.
The cast includes Gemma Chan, Angelina Jolie, Richard Madden, Brian Tyree Henry, Kit Harington, Lia McHugh, Lauren Ridloff and Barry Keoghan.
Eternals will be unveiled on 5 November in IMAX and cinemas across the UK.
Watch: Trailer for Eternals