Getting Eminem’s “Stan” into the mix was no small feat, but it helped pull together one of the SNL’s most ambitious sequences.

The Roots drummer and musical mastermind with Oscar and BAFTA awards, Ahmir “Questlove” Thompson, had a tall task in front of him: boil down five decades of Saturday Night Live musical moments into a single montage as he co-directed the new three-hour documentary “Ladies & Gentlemen…50 Years of SNL Music”. The intro sequence alone took nearly a year to create.

Together with music editor John MacDonald, Questlove compiled a master list of every song ever performed on the show. “We were like a Michelin star restaurant”, he told Variety, explaining how they broke down each track by tempo, key, and mood to find connections between them. The goal was to create seamless transitions that told a story across genres and generations.

Clearances, of course, became a major hurdle. One dream mashup — Mariah Carey, Christina Aguilera, and Pavarotti all hitting a climactic note — had to be scrapped when getting approval for two seconds of Pavarotti proved too costly and complicated.

But he did score a last-minute win: clearing Eminem’s “Stan”, thanks to Marshall Mathers and manager Paul Rosenberg. That brief inclusion helped link Stan with Destiny’s Child’s “Survivor” and NSYNC’s “Bye Bye Bye”. “You don’t know how hard and how difficult those 12 seconds were”, Questlove laughed.

The full montage took 11 months to assemble, but judging by the result, every second was worth it.

Watch Eminem’s Medley from Saturday Night Live (2017):