Kendrick Lamar‘s surprise project, untitled unmastered., arrived out of nowhere last Friday (Mar. 4), sparking an internet firestorm that centered on what, if anything, it all meant.

The eight tracks, all tied to a specific date but otherwise untitled, some taken from Lamar’s highly-praised live television performances and some seemingly left over from the sessions for his last album, To Pimp A Butterfly, were captivating in their variety and cohesion, with Lamar in top lyrical form throughout. Many were the result of sessions with Lamar’s core TPAB collaborators — Terrace Martin, Thundercat, Anna Wise and Sounwave — while others brought different energy to proceedings, with the likes of Hit-Boy, Cee Lo Green and even Swizz Beatz‘s five-year-old son Egypt all contributing to the project.

One of those tracks, called “untitled 6 | 06.30.2014,” features Green with soaring vocals over a track produced by Adrian Younge and A Tribe Called Quest member Ali Shaheed Muhammad. The song takes the form of a love letter, with Cee Lo’s voice over the jazzy production as the back drop for Lamar to spin a tale of accepting differences and embracing personal peculiarities and flaws. But the song wasn’t the product of a single studio session; instead, its origins date back further than the June 30, 2014 untitled-title indicates, originating as an instrumental that emerged from Younge and Muhammad’s upcoming joint album, The Midnight Hour, due out later this year. Billboard speaks with Young and Muhammad about the track’s origins, the existence of a Cee Lo-only version, and what they’ve got in store for 2016.

Billboard: At the risk of this sounding like an interrogation, where were you both on June 30, 2014?

Adrian Younge: [Laughs] We were actually all in a jail cell. We didn’t do it. To be quite honest with you, we don’t know what the exact reference to that date is. I’ll ask Kendrick about it later. But just to give you some background on the track, Ali and myself have an album coming out called The Midnight Hour. Now, The Midnight Hour, a couple years ago we had some demos, about six or seven demos for the album and we were looking for different artists to get on the album. When we hooked up with Cee Lo and gave him the demos, he was like, “Yo, I would love to get on this and do something,” and we were like, “Hell yeah, we’d love you to.” And he picked that instrumental and he sent us something that he calls “Question Marks.”

“Question Marks” is essentially what you’re hearing Cee Lo doing on this Kendrick track. So we got this demo, and when we got this back from Cee Lo, Ali and I were just totally taken aback on how well he killed it on that thing. And because of Sam Taylor — he was my old publisher at Sony and he’s at Kobalt now — he had hooked Ali and I up with Kendrick. And around that time we had played that track as well as some others for Kendrick, and he was like, “I need that song.” And we were like, “It’s not even finished yet,” and he was like, “I need that song.” So basically, he took Cee Lo’s unfinished demo and finished the song. So that’s what this “Untitled 6” is.

So it’s funny, because this is a song that we did for our album and then Kendrick was like, “I need this,” and we love him so we were like it’s all good. But while Kendrick finished his track, Cee Lo actually finished his track, which we’re still gonna put out on our album when we release it. So there will be two versions of this later in the year, but this one right now is the version we want everybody to gravitate towards and fall in love with. Kendrick murdered it.

Were you in the studio when he recorded it?

AY: We were not in the studio when he recorded this. He actually recorded this song around the time he was doing To Pimp A Butterfly. It was during that time frame, and we weren’t around for that; we got surprised with it, actually. Pleasantly surprised. We knew we had done the song a long time ago, but we didn’t hear the track until like a week ago.

What was your first reaction when you finally heard it?

Ali Shaheed Muhammad: Definitely surprised that he finished it. Really happy about it. First of all, I think Cee Lo laid such a foundation, and so I love the way that Kendrick picked up on what Cee Lo had put down, and the way that he followed the whole relationship subject matter in true Kendrick Lamar fashion. You know, I think he questions both sides of life, and some people can view life that way and look internally at their own reactions to things, not just through their own set of eyes, but through others’. I think he does that a lot, he does it really well. He really pushes the Gemini ideology, so just from the relationship perspective it’s just dope. And I think he continues to challenge the status quo in terms of MC skills and how to approach a song as a rapper. So I like it a lot.

AY: It’s one of those things where we were initially surprised from Cee Lo. Cee Lo, to me, his voice is classic; I’ve personally said to him before, “For me, your voice is as special as a Michael Jackson vocal,” because of what he can do, his range. I said that to him, and I mean that. And then you have another luminary, another icon in Kendrick on the track. So you have two iconic voices, two great writers on a track that Ali and I created as something that we just wanted for our album. And then it just turned into this. So we didn’t expect it. And it’s still something that we’re not over yet. It’s special, very special.

How much does Cee Lo’s version differ from this?

AY: There’s more verses from Cee Lo, there’s another hook. He did a great job; it’s just a totally different song.

ASM: I think the meaning is more realized, because there’s more of it from the verse, from Cee Lo’s perspective.

AY: It’s funny, because when people do hear this song, they’ll be able to listen to Kendrick’s and be able to listen to Cee Lo’s, and it’s the same vibe as far as the instrumentation, but it’s amazing to see how these two geniuses come vocally on the track. That’s what’s really crazy: to see how they both complete a song.

It kind of brings to mind the whole concept of how Kanye West never totally finished Pablo, and now there are different versions of those songs floating around. With this, you’ll have the Kendrick version and the Cee Lo version; it’s almost exploding the concept of what a “finished” song actually is.

AY: Right, for sure.

Are there any other things in the works for you guys?

AY: Actually, it’s funny you ask that; Ali and I are scoring a big television series that we can’t announce what it is yet, but it’s something that we’re scoring with a full orchestra. And it’s orchestrated by Miguel Atwood-Ferguson, so it’s something very special that we are looking forward to that everybody will be able to enjoy this year. So outside of the album that we’re doing, we’ve got the score of this big television series coming up.

What else can you tell me about the album?

ASM: I don’t think we should speak on the features yet.

AY: What we can say is, how the album started is the kind of music that A Tribe Called Quest would have sampled had these original tracks been around when they were making these classic albums. That’s where it started. It just kept going in a very creative, special, unique, novel direction to become what it is now. It’s pretty much complete; we got some touches that we still gotta do. But if you like this “Untitled 6” song, then you’ll definitely like this Midnight Hour album that we’ve got dropping this year.

Do you have a release date?

AY: It’s going to be contingent on when the television show is released, because we don’t to have them come out simultaneously. We want to have two lives with them. The television show, the release of that has not been officially locked yet, so we’re waiting on that. But what we can say is that it will be released this year.