Charli XCX’s new mixtape Pop 2 includes guest appearances by Carly Rae Jepsen, MØ, and Tove Lo, but there’s one major feature which didn’t make the final cut. In an interview with The Fader, the British singer revealed that one of the first collaborations recorded for the project was with the late Lil Peep.

Charli said she reached out after being inspired by Lil Peep’s music and was surprised he was willing to collaborate. After his recent death, however, the “Boom Clap” singer decided to leave the song off the mixtape:

We had a song that we did with Lil Peep that was going to be on this mixtape. And then now, it isn’t. I think it’s the right decision. I never met Lil Peep, but I was massively inspired by him. We just went out on a limb to try and get a feature with him, and completely to my shock, he actually did it. That was maybe the first song that we drafted for the mixtape, in London. It felt like…when we were brainstorming ideas for it, it was immediately him. It’s something that no one will ever hear, and that’s the way that it should be. I’m just honored that I got to do something with him.

In a separate interview with Vulture, Charli explained how quickly Pop 2 came together. After first mentioning it to producer A.G. Cook in London, they did the bulk of the work in New York during a five-day period:

Me and [producer] A.G. Cook… had this studio session [in London] where we made a few ideas… He flew over to New York for these really hectic, mental four or five days where we would stay in the studio until 4 a.m., and then we finalized everything. It was all being done while I was still on tour. In total, it took maybe two weeks. I would go into studios in L.A., Boston, Chicago, Austin, wherever and cut vocals. At the same time, I was sending shit to other artists asking them to jump on songs.

Charli also explained why she has has been recently releasing mixtapes instead of a traditional album. In addition to being hurt by album leaks, she said mixtapes are more conducive to her working style:

First of all, with the album, I don’t really know when I’m gonna put it out. Or even if I’m gonna put out an album. I just don’t know. And I think that’s what leads me toward making mixtapes. The way that I work and write is so fast, and releasing these mixtapes is very beneficial to that. I get so frustrated having to sit on music. I’ve been sitting on music for my album for so long now that people hacked me and leaked some music. For me to keep on being creative, doing these mixtapes is good.

In March, Charli shared her Number 1 Angel mixtape. As for the follow-up to her previous studio album Sucker, it looks to be on hold for now. However, rappers such as Young Thug, Lil Uzi Vert, and Lil Peep himself found most of their success without a proper studio effort, proving that making the distinction might not even matter.

Read all the lyrics to Charli XCX’s Pop 2 on Genius now.