If theres a word that best describes Questloves herculean effort to encapsulate the entirety of five decades of Saturday Night Lives musical legacy in one three-hour-long documentary, its diligence.

Thats on full display just in the first six minutes of the film, which debuts with an extensive cold open mashing up decades of performances by everyone from Billy Preston to Sabrina Carpenter, Gwen Stefani to Run-DMC and Dave Matthews Band to Queen, the whole number cohesively mixed to work with one another.

Its literally taking note of every musical moment, every note, Questlove (real name, Ahmir Thompson) tells THR as he hands over his phone to reveal a seemingly endless scroll of memos detailing genre, keys and tempo. The cold open took about 11 months to make. The notes we see, he says, are likely just from 1975 to 1985. Its every song ever played and then figuring out a 10,000-piece puzzle. Ladies and Gentlemen 50 Years of SNL Music was supposed to be a bit of a layup for the musician-director compared to, say, the exploration of the self-sabotage of Sly Stone in Sly Lives! (aka the Burden of Black Genius), with this project originally intended as a more modest collection highlighting 50 of the most iconic performances in the shows history. As that cold open alone reflects, that didnt happen. In Questloves own perfectionism and, as he says, self-sabotage, it had become a deep dive into the shows consistent window into pop culture as well as the weekly struggles and triumphs the show has created for those whove taken part.

I felt like, Well just make a really sophisticated clip show, and mid-recording, we started to notice an arc that keeps happening with every single story we get, Questlove says. Its a story of someone being presented with a daunting challenge, and its met with hesitancy, and its met with fear and trepidation. Is Jimmy Fallon going to knock on Mick Jaggers door and change his life? Will Eddie Murphy don a James Brown wig and sing about bubbling hot water for 30 seconds and change his life? What the hells Kanye going to do when he wears that hat on national television? Elvis Costello changing up the song in 1977 every story we go over, theres a risk factor.

The doc premiered Jan. 27 on NBC. NBCUniversal I wasnt expecting how much reverence youd give to the comedic music of SNL, whether thats Eddie Murphy or The Lonely Island. Was that something you knew youd do going into making the film?

Once we decided to get rid of the 50 best performances, I was like, Im gonna watch three to seven episodes every day. Thats when I realized, by 1984, especially when Eddie Murphy came aboard, there are way more iconic musical comedy sketches than there are musical performances. Once I started making a list of every performance moment, the comedy stuff was way in the lead. It became clear that we had to focus on both.

Going back to that risk factor and unpredictability, I thought you captured how much of a tightrope Saturday Night Live walks, how close it can all feel to just falling apart in real time.

Ive been at 30 Rock 30 Rock University for going on 17 years now. A lions share of my time off is making excuses to be [back] on the eighth or ninth floors. But the best way to experience SNL is absolutely [watching it] on television because its just two different experiences. The jokes land better on television because its one of the best-mixed shows on TV. Its silent in the studio, you have to be more quiet and not laugh as hard or you wont hear the next joke. But when the commercial comes on, thats when I come alive. Its like watching a demolition derby of five different ecosystems, and one false move and boom. (Hits his hand on the table.) Will a teamster crash into a prop guy? Will the wardrobe lady safely get our host over the musicians and back to the quick change booth? Watching the ecosystem and watching how it works, thats the thing that excites me.

You also highlight in the documentary how much more chaotic it gets when the musical guest is hosting.

The Lady Gaga show [in March] was probably the one thing that I dont think historian nerds are taking note of. She did a rarity: Shes in every single sketch when she hosted, and the musical presentations were elaborate. She has mere seconds to think. People ask what I would add now that the doc is shut; that would be it. When we shut the show down, Charli XCX [who hosted and was musical guest in December] was recording, and I begged production to let me go in post and just add one frame of Charli in there it was such a great episode. This was literally four or five days before airing, I was like, Look, I know we locked film already, but dog, let me fix this one frame, and I got my wish.

Youve probably watched more Saturday Night Live music moments than anyone else on the planet except maybe Lorne Michaels. Is there a performance you think is most emblematic of the show?

The performance that really just blew me away I actually decided not to put in the doc because if I couldnt put the whole five-minute performance in, you wouldnt have felt the energy of it. I didnt think I was going to learn anything from Neil Youngs Rockin in the Free World in 1990, but its just looking at five guys, just the equivalent of musical anvils dropping on your head. Its one of the loudest, most energetic performances I have ever seen.

This story first appeared in a May stand-alone issue of The Hollywood Reporter magazine. To receive the magazine, click here to subscribe.